Why the fuck did Satoshi implement the 1 MB blocksize limit?

[Anonymous Kid]

Okay okay, before you rush and say "To prevent spam attacks!!", please wait and read this whole thread.

^The above argument is what I hear all the time. However, there is something not quite right about that reasoning. It doesn't make sense.

Let's start with a little background info...

Satoshi implemented the 1 MB blocksize limit without telling anyone; He just did it randomly. There was no discussion beforehand and after he did it, he did not mention it anywhere. People had to look at the code/use it to see the change. The mannerism in which the 1 MB blocksize limit was added is already strange in itself and as soon as it was done, debates/arguments among the community started happening.

Satoshi never told people that the 1 MB limit was to prevent spam - its just what everyone inferred.

Okay... history lesson over.

Now here is why it doesnt make sense:

The process of a transaction getting confirmed and added to the blockchain goes like this:

1) Tx. is broadcast with a custom fee
2) Tx. is added to the mempool
3) Miner collects tx. from the mempool (usually they will pic tx. based on which has the highest fee and work their way down from there)
4) Miner adds tx. to their block
5) Miner calculates the proof of work
6) Miner publishes block to the blockchain

Okay now we have the process outlined we can analyse the miners incentives/behaviour. I'll be using game theory to explain this and here is where it gets interesting.

The miners main goal is to make profit. This is why he adds tx. to his block in the first place (it allows for more fees and thus, more profits). So we can assume that without the blocksize limit, the miners would add infinite tx. to their block right? WRONG!

Allow me to explain:

Look at step 3.. Collecting the tx. from the mempool and adding it to their block takes a set amount of time and the longer that the miner spends collecting the tx. and adding it to their block, the less time they can spend calculating the proof of work - thereby giving their competition (other miners) the edge. The miners would naturally (based on game theory) find a nash equilibrium between collecting as many tx. as possible and finding enough time to calculate the proof of work in order to give them the maximum profitability. Thus, we can assume, that without a blocksize limit (infinite), the block size would stay relatively the same.

This is why an infinite block size limit is not an issue. I honestly cannot understand why he added the 1 MB limit.
Can someone please, please explain? I have been pondering this for over a month now. Thanks.

[Selenites]

Because he does what he want, he's a grown man leave him alone! And have some respect boy!!
He's the godfather of the new world

[Anti-Cen]

Because he does what he want, he's a grown man leave him alone! And have some respect boy!!
He's the godfather of the new world

Yes new world alright where we now have CPU-Wars between miners, all 20,000 of them here
on Bitcoin and a system that was known from day one would not scale and no one knows who
Satoshi is because the chances are he was working for the CIA or MOSSAD

Please feel free to join me and defend the block-chain and insist Lightning Network does not take
transactions "off-block" to defend his name because other systems like Neo and Ripple can scale the block-chain and do
1000 time more than seven transactions a second.

Learn to think for yourself instead of praying to the fruit machine

[Anti-Cen]

This is why an infinite block size limit is not an issue. I honestly cannot understand why he added the 1 MB limit.
Can someone please, please explain? I have been pondering this for over a month now. Thanks.

I make a good living writing software and it would had been obvious to anyone that has worked
on scaleable system that as implemented Bitcoin could never scale and ETH has played around
with block sizes and timing has manged to speed the BC up from seven transactions per second
to fifteen but you won't get much more than that.

Distributed computer systems break the work down (200gb of files) across servers with redundancy
built in so what we have left is Micky Mouse software and not only is it falling over but the lightning
network is fixing the problem at the wrong level and these hub things ! Well they are mini banks and
you can run one yourself if you have lots of BTC and hardware just like the miners have already and
hope you won't be locked out by the cartel

Don't worry if you get attacked because most people here have a vested interest in papering
over the cracks and making out that everything is fine when its not

[sjyi]

...Satoshi implemented the 1 MB blocksize limit without telling anyone; He just did it randomly. There was no discussion beforehand and after he did it, he did not mention it anywhere. People had to look at the code/use it to see the change. The mannerism in which the 1 MB blocksize limit was added is already strange in itself and as soon as it was done, debates/arguments among the community started happening.

Satoshi never told people that the 1 MB limit was to prevent spam - its just what everyone inferred.[/i]
...
This is why an infinite block size limit is not an issue. I honestly cannot understand why he added the 1 MB limit.
Can someone please, please explain? I have been pondering this for over a month now. Thanks.

As Satoshi never told anyone why he did this, I certainly don't know the reason either.  But I do have experience designing and implementing software systems.  When you initially design a new system, regardless how much you calculate, model or simulate, you just have to decide some parameters and move on.  I think the block size could be one of those items where he needed to pick something and move on to finish the system.

[CryptoRyuzaki]

@OP, I agree with your argument. As per game theory and the assumptions you have made, I don't see a reason why the block size limit has to stay at 1 MB.

Newbie question here, is there any way to change the block size limit? How feasible it is to do? Would it require a hard fork?

[dinofelis]

Great question !

Okay okay, before you rush and say "To prevent spam attacks!!", please wait and read this whole thread.

^The above argument is what I hear all the time. However, there is something not quite right about that reasoning. It doesn't make sense.

Let's start with a little background info...

Satoshi implemented the 1 MB blocksize limit without telling anyone; He just did it randomly. There was no discussion beforehand and after he did it, he did not mention it anywhere. People had to look at the code/use it to see the change. The mannerism in which the 1 MB blocksize limit was added is already strange in itself and as soon as it was done, debates/arguments among the community started happening.

Satoshi never told people that the 1 MB limit was to prevent spam - its just what everyone inferred.

Okay... history lesson over.

Now here is why it doesnt make sense:

The process of a transaction getting confirmed and added to the blockchain goes like this:

1) Tx. is broadcast with a custom fee
2) Tx. is added to the mempool
3) Miner collects tx. from the mempool (usually they will pic tx. based on which has the highest fee and work their way down from there)
4) Miner adds tx. to their block
5) Miner calculates the proof of work
6) Miner publishes block to the blockchain

Okay now we have the process outlined we can analyse the miners incentives/behaviour. I'll be using game theory to explain this and here is where it gets interesting.

The miners main goal is to make profit. This is why he adds tx. to his block in the first place (it allows for more fees and thus, more profits). So we can assume that without the blocksize limit, the miners would add infinite tx. to their block right? WRONG!

Allow me to explain:

Look at step 3.. Collecting the tx. from the mempool and adding it to their block takes a set amount of time and the longer that the miner spends collecting the tx. and adding it to their block, the less time they can spend calculating the proof of work - thereby giving their competition (other miners) the edge. The miners would naturally (based on game theory) find a nash equilibrium between collecting as many tx. as possible and finding enough time to calculate the proof of work in order to give them the maximum profitability. Thus, we can assume, that without a blocksize limit (infinite), the block size would stay relatively the same.

This is why an infinite block size limit is not an issue. I honestly cannot understand why he added the 1 MB limit.
Can someone please, please explain? I have been pondering this for over a month now. Thanks.

There are three possible answers:

1) Satoshi didn't completely understand the implications of his random choice, which seemed reasonable at the time to him.  

2) Satoshi knew very well what he was doing, was an evil mind, and he was lying through his teeth all the time, to trick us into his nonsense.

3) Satoshi was a true god and genius, and even though we think he might have made a mistake, he was absolutely right in everything he ever did and we are simply too dumb to see it.

There have been a lot of discussions over that issue, and people warned Satoshi that his random decision was recipe to disaster.

The truth is maybe in the 3 things at once.  It is obvious that the spam limit is a joke.  In fact, it makes spam worse.  The excuse was that if a fool mined a single block of 10 GB full of nonsense, the blockchain would be spammed to an incredible size in no time.  That was clearly wrong, because in order for that block to be incorporated into the chain, other miners would have to agree with it.  There's no reason why honest miners would mine on top of a crazy block.  In other words, implicitly, there would be a gross maximum size set by miners and that would grow dynamically.

By putting a hard limit on block size, you actually increase drastically the effect of spam, as we saw.  Once the block is full of spam, transactions are hindered.  This is an efficient DDOS of bitcoin.  If the blocks are elastic, you can spam a lot, that will increase the size to some point, but transactions can go through unhampered, and you'd have to spam like crazy in order to have an efficient DDOS.  Hard limits make DDOSsing of bitcoin in fact much easier.

Satoshi was clearly in favour of very large blocks if useful, and he explains that in the beginning, where he tells us that most normal users shouldn't run a full node, "left to specialists with farms of specialized hardware".  That was in November 2008.

People explained him that putting a hard limit in the protocol would require a hard fork at a point, which might be problematic.  He wavered that away: just changing a constant in the code.

Maybe Satoshi did put a "time bomb" in his bitcoin system because he considered it an experiment from which we have to learn, and it should self-destroy at a certain point in order for us to make a new system with better properties.  Maybe Satoshi wanted to put in a trap, so that only if his heirs were smart enough to have good governance, and if they cannot even change a simple parameter, then it is better that this system dies.  Maybe Satoshi wanted to develop a whole crypto market, and needed to put something nasty in bitcoin, in order to make it lose its first mover advantage and open up the market.

Maybe Satoshi was designing a reserve currency for big, dark, deep state players, and only needed Joe Sixpack to ramp it up, but needed him to be pushed out of bitcoin once the system was up and running, to leave it to the big boys.  Claiming it to be a currency of the people, but at the same time, making its use too expensive for the people, and only allow the big boys on it, was maybe his hidden plan.

But I think that Satoshi simply made a mistake.  He made many.  Bitcoin is quite ill designed.  That doesn't take away the fact that he was a bright mind.  We have hindsight he didn't have.  But he was wrong on this one, as he was wrong on many choices.

[joktel]

You said infinite chain size is not an issue and you are also of the opinion that limiting the size had no effect. I think you already answered your question... He added a neutral protocol that is not imprescindible but useful

[bakerlisa510]

I don't know why people are answering full of nonsense things in relation to the question.!!

I believe the secret of 1MB blockchain lies within  Mr. Nakamoto unacknowledged which he doesn't want to share with the world.

[Kakmakr]

The Block size limit was never meant to be fixed. Satoshi knew that transactions would increase over time, but he had to implement a starting point. He did talk with other people like Gavin / Hall / Nick and others, but a increase in the Block size would have been overkill at the time.

Bigger Block sizes could also lead to more spam and it might have been percieved as a possible attack vector. <It was still very experimental back then>

[Turkish88]

technical progress go faster then Mr. Nakomoto think.
Big block size in 2009 have issues with network speed

[CryptoRyuzaki]

Great question !

Okay okay, before you rush and say "To prevent spam attacks!!", please wait and read this whole thread.

^The above argument is what I hear all the time. However, there is something not quite right about that reasoning. It doesn't make sense.

Let's start with a little background info...

Satoshi implemented the 1 MB blocksize limit without telling anyone; He just did it randomly. There was no discussion beforehand and after he did it, he did not mention it anywhere. People had to look at the code/use it to see the change. The mannerism in which the 1 MB blocksize limit was added is already strange in itself and as soon as it was done, debates/arguments among the community started happening.

Satoshi never told people that the 1 MB limit was to prevent spam - its just what everyone inferred.

Okay... history lesson over.

Now here is why it doesnt make sense:

The process of a transaction getting confirmed and added to the blockchain goes like this:

1) Tx. is broadcast with a custom fee
2) Tx. is added to the mempool
3) Miner collects tx. from the mempool (usually they will pic tx. based on which has the highest fee and work their way down from there)
4) Miner adds tx. to their block
5) Miner calculates the proof of work
6) Miner publishes block to the blockchain

Okay now we have the process outlined we can analyse the miners incentives/behaviour. I'll be using game theory to explain this and here is where it gets interesting.

The miners main goal is to make profit. This is why he adds tx. to his block in the first place (it allows for more fees and thus, more profits). So we can assume that without the blocksize limit, the miners would add infinite tx. to their block right? WRONG!

Allow me to explain:

Look at step 3.. Collecting the tx. from the mempool and adding it to their block takes a set amount of time and the longer that the miner spends collecting the tx. and adding it to their block, the less time they can spend calculating the proof of work - thereby giving their competition (other miners) the edge. The miners would naturally (based on game theory) find a nash equilibrium between collecting as many tx. as possible and finding enough time to calculate the proof of work in order to give them the maximum profitability. Thus, we can assume, that without a blocksize limit (infinite), the block size would stay relatively the same.

This is why an infinite block size limit is not an issue. I honestly cannot understand why he added the 1 MB limit.
Can someone please, please explain? I have been pondering this for over a month now. Thanks.

There are three possible answers:

1) Satoshi didn't completely understand the implications of his random choice, which seemed reasonable at the time to him.  

2) Satoshi knew very well what he was doing, was an evil mind, and he was lying through his teeth all the time, to trick us into his nonsense.

3) Satoshi was a true god and genius, and even though we think he might have made a mistake, he was absolutely right in everything he ever did and we are simply too dumb to see it.

There have been a lot of discussions over that issue, and people warned Satoshi that his random decision was recipe to disaster.

The truth is maybe in the 3 things at once.  It is obvious that the spam limit is a joke.  In fact, it makes spam worse.  The excuse was that if a fool mined a single block of 10 GB full of nonsense, the blockchain would be spammed to an incredible size in no time.  That was clearly wrong, because in order for that block to be incorporated into the chain, other miners would have to agree with it.  There's no reason why honest miners would mine on top of a crazy block.  In other words, implicitly, there would be a gross maximum size set by miners and that would grow dynamically.

By putting a hard limit on block size, you actually increase drastically the effect of spam, as we saw.  Once the block is full of spam, transactions are hindered.  This is an efficient DDOS of bitcoin.  If the blocks are elastic, you can spam a lot, that will increase the size to some point, but transactions can go through unhampered, and you'd have to spam like crazy in order to have an efficient DDOS.  Hard limits make DDOSsing of bitcoin in fact much easier.

Satoshi was clearly in favour of very large blocks if useful, and he explains that in the beginning, where he tells us that most normal users shouldn't run a full node, "left to specialists with farms of specialized hardware".  That was in November 2008.

People explained him that putting a hard limit in the protocol would require a hard fork at a point, which might be problematic.  He wavered that away: just changing a constant in the code.

Maybe Satoshi did put a "time bomb" in his bitcoin system because he considered it an experiment from which we have to learn, and it should self-destroy at a certain point in order for us to make a new system with better properties.  Maybe Satoshi wanted to put in a trap, so that only if his heirs were smart enough to have good governance, and if they cannot even change a simple parameter, then it is better that this system dies.  Maybe Satoshi wanted to develop a whole crypto market, and needed to put something nasty in bitcoin, in order to make it lose its first mover advantage and open up the market.

Maybe Satoshi was designing a reserve currency for big, dark, deep state players, and only needed Joe Sixpack to ramp it up, but needed him to be pushed out of bitcoin once the system was up and running, to leave it to the big boys.  Claiming it to be a currency of the people, but at the same time, making its use too expensive for the people, and only allow the big boys on it, was maybe his hidden plan.

But I think that Satoshi simply made a mistake.  He made many.  Bitcoin is quite ill designed.  That doesn't take away the fact that he was a bright mind.  We have hindsight he didn't have.  But he was wrong on this one, as he was wrong on many choices.

Wow! This response gave me lot of possible scenarios which I didn't think of! Thanks for the great insight/thoughts @dinofelis

Among all the possible scenarios listed, my personal favorite is:

Maybe Satoshi did put a "time bomb" in his bitcoin system because he considered it an experiment from which we have to learn, and it should self-destroy at a certain point in order for us to make a new system with better properties.  Maybe Satoshi wanted to put in a trap, so that only if his heirs were smart enough to have good governance, and if they cannot even change a simple parameter, then it is better that this system dies.  Maybe Satoshi wanted to develop a whole crypto market, and needed to put something nasty in bitcoin, in order to make it lose its first mover advantage and open up the market.

[dinofelis]

technical progress go faster then Mr. Nakomoto think.
Big block size in 2009 have issues with network speed

On the contrary.  Satoshi knew very well how to do it, and explained it here:

http://satoshi.nakamotoinstitute.org/emails/cryptography/2/

His idea was that there would be a few (100 - 1000 ?) full nodes/miners "with specialized hardware", who are the "Facebook servers" of the block chain, and all users simply connect with light SPV wallets.  He considered 100 GB/day block chain growth not a problem, because only these "nodes with specialized hardware" had to keep them.  So, grossly, he was considering 100MB blocks.

The narrative that every Joe needed a copy of the full block chain in his basement is Core narrative, not Satoshi narrative.

Satoshi never seemed to have publicly seen the difficulty of "hard forks".  In as much as he understood immutability of the past ledger, he didn't seem to have bothered about the same immutability mechanism for the rules (the protocol).  So changing a parameter didn't seem like a lot of troubles, even though people pointed out the danger of it "locking in".

[drwhobox]

There are a lot of things that can be with Satoshi's mind at that moment which in his/her mind can be good with that 1mb limit per block. Satoshi did not even think that this would came on what we do have not and the demand for Bitcoins could come as far as this. That's why soft forks and hard forks came to the network just to get what the community want and need for the betterment of Bitcoin.

[ranochigo]

Collecting the tx. from the mempool and adding it to their block takes a set amount of time and the longer that the miner spends collecting the tx. and adding it to their block, the less time they can spend calculating the proof of work - thereby giving their competition (other miners) the edge. The miners would naturally (based on game theory) find a nash equilibrium between collecting as many tx. as possible and finding enough time to calculate the proof of work in order to give them the maximum profitability. Thus, we can assume, that without a blocksize limit (infinite), the block size would stay relatively the same.

I don't run a mining pool nor do I have access to their code. However, I'm under the impression that the construction of the merkle root should not take that much of a time. While the miner focuses on the fees aspect, the miner should be able to just grab the transaction with the highest fee immediately after they verify the block and remove the relevant transactions. Either way, I feel that the block size would serve as a gauge for a controlled growth such that people would still be able to run a full node and have an estimate on its storage in the future.

That was clearly wrong, because in order for that block to be incorporated into the chain, other miners would have to agree with it.  There's no reason why honest miners would mine on top of a crazy block.  In other words, implicitly, there would be a gross maximum size set by miners and that would grow dynamically.

I agree with you on the 1GB part. But it isn't if the miner would agree with it but its with the fact that the propagation would be so slow, such that the chances of it being orphaned is incredibly high.
I feel that the main motivation behind this is that big blocks wouldn't be able to be handled by the internet for most of the nodes at that time.

[Carlton Banks]

infinite block size limit is not an issue. I honestly cannot understand why he added the 1 MB limit.

Use Bitcoin Cash

@OP, I agree with your argument. As per game theory and the assumptions you have made, I don't see a reason why the block size limit has to stay at 1 MB.

Newbie question here, is there any way to change the block size limit? How feasible it is to do? Would it require a hard fork?

Use Bitcoin Cash

By putting a hard limit on block size, you actually increase drastically the effect of spam, as we saw.  Once the block is full of spam, transactions are hindered.  This is an efficient DDOS of bitcoin.  If the blocks are elastic, you can spam a lot, that will increase the size to some point, but transactions can go through unhampered, and you'd have to spam like crazy in order to have an efficient DDOS.  Hard limits make DDOSsing of bitcoin in fact much easier.

Use Bitcoin Unlimited (and maybe you should troll more consistently, you were arguing for months about how 1MB would be the blocksize forever. Until it was replaced by the 4MB blockweight, and now you're not Mr. 1MB, you're Mr. Infinite. Riiiiiiiiight)

[dinofelis]

Use Bitcoin Unlimited (and maybe you should troll more consistently, you were arguing for months about how 1MB would be the blocksize forever. Until it was replaced by the 4MB blockweight, and now you're not Mr. 1MB, you're Mr. Infinite. Riiiiiiiiight)

I said: bitcoin will not undergo a fork until it has lost its total market dominance, because bitcoin only has its brand name to go for.  Once the brand monopoly will be gone, they will finally maybe move their asses and do something that works.  Right now, bitcoin doesn't work well.  Pseudo-4MB or not.
Well, that's more or less what happened: bitcoin is now at 1/3 of the market cap, the forking fear is gone, bitcoin now has two viable clones in the top 20 and as far as I know, bitcoin is still at its 1 MB block limit after the segwitx2 failure, no ?  Given the competition of bitcoin cash, and the fact that bitcoin, finally, did fork, rendered the power monopoly of Core moot.  When it will have become a moot point, I guess suddenly for core, the holy 1 MB block limit will not be a problem any more, they will invent another narrative.... and it won't matter any more, because they overplayed their hand, split bitcoin over their pet story, and removed bitcoin as the market monopolist.  Which is a very good thing.  Brand monopoly is a bad thing, and competition improves everyone.

[ranochigo]

Right now, bitcoin doesn't work well.  Pseudo-4MB or not. Well, that's more or less what happened: bitcoin is now at 1/3 of the market cap, the forking fear is gone, bitcoin now has two viable clones in the top 20 and as far as I know, bitcoin is still at its 1 MB block limit after the segwitx2 failure, no ?

Nope. Since the Segwit's activation, its theoretical size would be about 2MB (if everyone uses Segwit). The size concept is now based on the transaction weight which doesn't require a hard fork. Isn't the prices affected mostly by the problem with the regulations?

Given the competition of bitcoin cash, and the fact that bitcoin, finally, did fork, rendered the power monopoly of Core moot.  When it will have become a moot point, I guess suddenly for core, the holy 1 MB block limit will not be a problem any more, they will invent another narrative.... and it won't matter any more, because they overplayed their hand, split bitcoin over their pet story, and removed bitcoin as the market monopolist.  Which is a very good thing.  Brand monopoly is a bad thing, and competition improves everyone.

I'm not particularly fond of hard forks for Bitcoin. It's a lot harder to do than a soft fork. Lightning network could help with the issue.

I would say that the fact that the prices of the other coins are so high could be because of Bitcoin's name. Afterall, they do contain "Bitcoin". Would be safe to say that their trading volume is due to miners and those coins being brought over with the fork.

[Easteregg69]

Why did Satan never get the chance to walk the earth ? Perhaps the old man decided to spare one son. How should i know what Satoshi thought was right ?

For now you can call satoshi a corporation including Toshiba.

[dinofelis]

Right now, bitcoin doesn't work well.  Pseudo-4MB or not. Well, that's more or less what happened: bitcoin is now at 1/3 of the market cap, the forking fear is gone, bitcoin now has two viable clones in the top 20 and as far as I know, bitcoin is still at its 1 MB block limit after the segwitx2 failure, no ?

Nope. Since the Segwit's activation, its theoretical size would be about 2MB (if everyone uses Segwit). The size concept is now based on the transaction weight which doesn't require a hard fork. Isn't the prices affected mostly by the problem with the regulations?

Segwit has advantages, but the trick of only counting half of the real data and claiming it makes a difference is very cheap.  A transaction, whether segwit or legacy, takes about the same amount of data, except that you don't count everything in the main block with Segwit. But for storage and transmission, that's the same burden.

In reality, Segwit didn't do zilch to the actual amount of bitcoin transactions per block:

https://blockchain.info/charts/n-transactions-per-block?daysAverageString=7

No big increase has been seen when segwit got activated end of August 2017.

People don't really use it, even given the high fees:

http://segwit.party/charts/

Segwit is good, but for a totally different reason: atomic swaps.  

Given the competition of bitcoin cash, and the fact that bitcoin, finally, did fork, rendered the power monopoly of Core moot.  When it will have become a moot point, I guess suddenly for core, the holy 1 MB block limit will not be a problem any more, they will invent another narrative.... and it won't matter any more, because they overplayed their hand, split bitcoin over their pet story, and removed bitcoin as the market monopolist.  Which is a very good thing.  Brand monopoly is a bad thing, and competition improves everyone.

I'm not particularly fond of hard forks for Bitcoin. It's a lot harder to do than a soft fork. Lightning network could help with the issue.

I would say that the fact that the prices of the other coins are so high could be because of Bitcoin's name. Afterall, they do contain "Bitcoin". Would be safe to say that their trading volume is due to miners and those coins being brought over with the fork.

I think that hard forks are good things :they are THE way to have decentralized "governance".  Instead of voting and killing of the "smart minority", it acts like biological evolution.  The mutant is maybe in minority, but it can fill its ecological niche, and maybe even exterminate the parent species if it is superior.  Most mutants die immediately.  But some survive, and some may even exterminate the parent.  Hard forks are nature's way to improve biology, and they are the free market equivalent as compared to state-planned economies based upon a parliament voting.

In any case, the whole block size debate was full of deception and disinformation, and the hard block limit in bitcoin was/is a bad thing for the strain of bitcoin that contains it.  Hence the good OP question.  Satoshi made a mistake, or wanted to put a bomb in bitcoin by doing so, or thought it would be no issue to change it.  There's absolutely no sense in hard-limiting block size without limiting the system's utility at the same time.  If bitcoin is at 1/3 market cap right now, it is because of this block limit (and the very bad way of handling it by Satoshi's heirs).

I would even say that a massive LN on top of a hard-limited block chain is suicide, because of the danger of massive settlement.  With flexible blocks, settlements will always be possible.  On a block-limited chain, settlements are also restricted, making the "settlement run" instead of a "bank run" a genuine possibility.  A well-targetted spamming campaign combined with a settlement panic could be fun to watch.

In summary, no argument holds for hard block limits, and the final argument "my goodness, it is a hard fork" is now done too, because, hey, hard forks happened already.