Emergent consensus is not elimination of block size restriction. Miners will always restrict size because there is a cost to increasing it.
This is just pure wishful thinking totally unsupported by any analysis, experimental or calculable proof.
When BU forms a chain, it will take one, and only one, 'valid' malicious block to ruin that chain forever. Any BUcoin will exist forever with that Sword of Damocles hanging over it. On that one fatal security flaw alone it is not a serious contender for solving capacity expansion for bitcoin.
Most Core developers understand this, it is not obstinacy that they will not 'compromise'. Any requests to 'compromise' is asking Core devs to acquiesce to the possible ruination of bitcoin, why would they sign off on opening bitcoin up to that? All they can do is put forward their solution and see if it is accepted. You cannot coerce or guilt-shame developers into writing code they know is risking the complete ruination of the project by opening it up to an obvious existential security flaw. If Core dev's proposed solution is maligned enough to be found unaccepted then all they can do is shrug and say, "we tried".
No security coder is going to write known compromised software voluntarily.