Mainchain blocksize stays the same, but if competitive miner revenue comes to depend on mining a drivechain, that potentially changes the game in a big way, much like big blocks.

I don't give a flying fuck what bcashers want. I want to scale Bitcoin without gambling with major incentives. Something like the new spiderchain proposal or tokens on lightning sound much more promising. Lets make use of the many unused features that already exist before we start forking things again.