But without users on board that would be an exercise in stupidity and futility

So the only viable way for them to "fork off" is to take the Bitcoin blockchain (otherwise no one would seriously consider their Bitmaincoin as Bitcoin at all) with all the transactions and Bitcoin balances. But that would instantly mean a war, a devastating war of blockchains that would be rather interesting to watch (provided you don't have any bitcoins) but which would most certainly lead to Bitcoin total annihilation within a couple of weeks

That shows a best share of less than 6.2 million; if you found a block, it wasn't a Bitcoin block (which has a diff of 711,697,198,173). An error in the Antminer firmware, maybe?

What I see happening is BIP148 user activated soft fork will be a miserable failure but it won't matter. By that stage most pools will be signalling segwit thanks to segwit2x. Segwit will get activated and then fees will remain low, blockstream will not commandeer the blockchain, lightning network will not centralise transactions, nothing bad will happen and everyone will wonder what the fuck all the fuss was about. There will be no need for antpool with Jihan at the helm to create an aggressive hard fork against UASF; that was always a bullshit powerplay "I want my lollipop back" from Jihan as a counterthreat to UASF which hasn't got anywhere near enough traction to be relevant anyway. So nothing will happen to diff, there will be no fork, there will be no change of PoW. Forget the talk of diff drop to 2014 levels; that's off the cards entirely. The confidence that consensus will instil in the market will be reflected by yet more BTC value increases... till the next phase. The fun part is now that most of the pools are agreeing on what to signal next, transaction fees have suddenly plummeted due to total transactions plummeting - which means it's almost certain that someone amongst the pool groups was the architect behind the transaction flood which made it look like there was a transaction block space crisis. There's no economic reason for the total number of transactions to crash the way they have over the last week with BTC value being so strong right now.

After that people will be left scratching their heads wondering if we even need a 2MB block size increase at this time, but because all the pools made such a fuss about it, we'll have our next debate, but the pools have already insisted they want a block size increase and signed the NYA. I'm not sure how core will respond at that stage because that will be the true test of whether the miners can effect a change in consensus - but despite all the anti-core rhetoric, core dev has always overwhelmingly said they would do a block size increase but with a much slower time frame than that proposed by segwit2x simply because the regression testing required to confirm a hard fork is safe is substantial. I predict we'll get a 2MB base blocksize increase as well, though how and when I can't tell at this stage.

By the way, the current segwit2x "signalling" is just a show of support in their coinbase signature and doesn't change the way anything operates. However what it is saying is that they will be actively signalling from mid-July for segwit.

By the way, if you've all only been remotely watching the scaling debate from a distance, segwit2x appears to truly gaining enough traction to bring segwit activation to the fore.

The pools that signed the agreement just started signalling for it and it is taking off faster than any other scaling signalling. See:
https://coin.dance/blocks

Unlike the original proposal, it includes BIP91 meaning it is compatible with core's segwit now. The rapid adoption of segwit2x, which with the addition of BIP91 means that miner activated segwit is now likely on the horizon at last, and since there is overwhelming support for it and the associated 2MB hardfork in the future, that may also follow.

lighting network is the only way bitcoin or any other blockchain system to become mainstream as an everyday payment system or everyday smart contract system. Is technical impossible right now a blockchain system to have Visa, Paypal onchain volume. To do this it needs 500mb-5gb blocks. this is ridiculous for everyone to say that bitcoin can upgrade to this level onchain.
Miners must accept that the future is in sidechain payment or lighting network and for the first time to start to develop their own tech solutions around it to begin to get profit from them. Because until now every day they payed from the others work without to return anything back to the ecosystem.