I don't see how. Please explain how consensus around increasing the blocksize is ever going to happen? Because again, it will only lead to 2 things:
1) Bitcoin will continue with 1MB as there will still be people mining and transacting on it
2) There will be a 2MB or whatever blocksize hardfork, which companies and exchanges will claim it's Bitcoin, even if Core team agrees, it doesn't make it Bitcoin
So you will have the legacy chain existing and the new chain existing, and we already have this (Bcash).
The blocksize cannot be increased, it will always lead to a new altcoin, which some may call Bitcoin. Bitcoin is basically impossible to hardfork at this point (without again, ending up with 2 coins).
Consensus means, that the majority of the participants are willing to follow those rules.
And I'm quite sure that at some point in time the majority will agree with a block weight increase.
Let me think about the different roles who are part of the bitcoin network.
The following list is just my opinion of what the different roles could think. I might be wrong, so feel free to correct or extend this list.
- Miners
Most miner would be for an increase of the block weight as they could pack immediately more transactions into one block which would increase their collectable fees.
Some miners with a bad internet connection might be against it, as they would have a disadvantage as bigger blocks would get broadcasted a bit slower which means they have a bigger delay to start mining a new block. - Full Nodes
Depending on how big the increase will be, the people who run full nodes will need to check if their current CPU power is high enough to be able to validate incoming transactions and blocks in time, if they have enough disk space to store the blockchain and if their bandwidth is high enough to be able to download and propagate received blocks to connected peers.
The CPU power will not be a limited factor as even with a x4 block weight increase a Raspberry Pi could still easily handle this load.
Also disk space is not a problem today with an increased block weight.
The bandwidth is usually the limiting factor. Not the download speed, it's more the upload speed.
So, if the increase would be too high this could mean that some people could stop or limiting providing their full nodes. - Users
Normal users usually only want a good experience. With increased block weight, transactions would get confirmed faster and that's what is important for them. - Companies
Companies, as seen in the past with support of the 2X will be happy with an increase of the block weight. I don't see that they would be against it. - Core Developers
Core developers want to keep the network as secure and as decentralized as possible. When they see that an increasing of the block weight does not have a big impact on security and decentralization, the majority will also be for an increase.
As the infrastructure (CPU power / bandwidth / hard disk storage) increase over time, so they will allow also an increase of the block weight with about the same rate. This will more or less guarantee that the network don't get more centralized
When a fork for increasing the block weight is agreed, I think there will be not only an increase of the block weight but also some other new features which require a hard fork.
As a hard fork is always dangerous, you should get the most out of it to avoid another hard fork after a short time.
Combined with also new features a hard fork might be more interesting also for those people who are against a block weight increase on it's own.
Such a hard fork will also need a preparation from I guess about 1 year. So there is time that everybody get notified about the hard fork and have time to update their software.
But of course there is a big chance that a chain split happens as it's hard to get everyone on board.
There will be a legacy chain and a forked chain. But if the majority was for a consensus change, the most value will be on the forked chain and just a small part will stay on the legacy chain. Maybe the legacy chain will die after some time, maybe it will continue like Ethereum Classic or maybe it keeps the most value. This decision will then be made by the market.
BCash was a fork without overall consent, that's the reason why it just become an alt coin. If BCash would had the majority on their side or if the Segwit2X would have been successful with the majority on their side (which would also be represented by the market value), this winning fork would be the new bitcoin in my eyes.