The problem is, if your "solution" is outside of the consensus of the Bitcoin protocol, it's a non-solution, because now you have a consensus problem. There were somewhere near 100 "solutions" proposed during the blocksize war, each of them more arbitrary than the next.

The most dangerous and centralizing on practically every level action that can be taken to "fix a problem" is to fork consensus. There is little that can be done that exposes more risk to the entire Bitcoin network and ecosystem than this. And to take this enormous, impossible coordination action for the sake of what? 2MB, 10 MB blocks? Which are less than a drop in the ocean compared to the scaling problem.

There are 100 other reasons why its a bad idea, but the two facts alone; that its the most dangerous & centralizing thing we can do, and it does literally nothing for the long term scaling problem, is enough to throw the option in the trash, imo.