@Mengerian The talk of fork arbitrage on the Core side, and them seeing the advantages of it, has been a long time coming.
Fundamentally, small blockers should be eager for a hard fork where they can make money off us "fools" in the trading, yet strategically Core's lockdown of the blocksize setting and theymos's censorship must appear to many small blockers as beneficial to their cause. They turn a blind eye to the irony of turning to central planning to maintain decentralization, and resorting to censorship to maintain censorship resistance.
For now.
But what happens if the cat is out of the bag, a hard fork is recognized as imminent, and Core jiggering is no longer effectual? Perhaps Core gives in and lets users adjust the blocksize while still sternly recommending 1MB (the only way they can stop their market-share bleeding without actually endorsing a higher blocksize limit). Then we have achieved an EC world and we return to a cleaner debate just over blocksize, uncomplicated by dev team considerations.
When any forks to bigger blocks are tried, it will then be purely a matter of investor uptake. It will become clear to all the futarchic situation whereby Bitcoin is ruled by a prediction market (especially when fork futures start trading*).
In some ways, any talk of fork arbitrage already represents a movement to dethrone Core, either directly through adoption of other implementations, or indirectly by forcing them to stop rigging consensus with their hardcoded blocksize caps.
People wonder about ledger immutability, since the Ethereum split showed investors can back ledger mutation, leaving one to wonder where true ledger immutability comes from. I hope it will soon be clear to all that ledger immutability comes from the fortitude of the investors in the ledger, that more generally the investors control the effective (read: valued on the market) direction of governance, and that every hard fork is a new chance to enrich the best stewards and thereby increase their influence while systematically removing the worst stewards from having any influence at all.
*Imagine if exchanges had a mechanism set up for fork futures where anyone could apply to have an upcoming fork be tradable. You specify certain conditions and, like on the prediction market sites, a proposition is opened for people to bet on.
