My point is that if YouTube stopped working on Firefox because they didn't agree to a new standard Google had invented, lots of people would stop using Firefox.

My point is that if YouTube stopped working on Firefox because they didn't agree to a new standard Google had invented, lots of people would stop using Firefox. It takes someone who really cares about these issues to bother switching back and forth between two different browsers because you want to use a non-Chromium for most things but have to use Chromium for a couple of things. The vast majority would just say "well, whatever" and switch completely.