"Guilty of losing patience" is nonsense. If you look at the process by which web standards advance, it requires that two or more vendors have created proof-of-concept implementations, before the standard can be standardized. That, in fact, how standards have always worked.

As a Firefox user, I don't like the results either. But I don't think any of the actors in question are acting in bad faith. Not even the lazy web developers who build Chrome-only games; why should they build shit for me, if they don't want to?

I'm a web game builder and I'm definitely guilty of that. However, I make the games for myself. If other people want to play, fine, but I have no personal reasons to support anything other than my own setup. I presume a lot of other indie game developers are the same. I don't make any money on the games and have neither time, resources nor interest in making it compatible for browsers I don't use.

Yeah, this is pretty much it. I definitely have tried with a lot of browsers, I learnt about a lot of quirks of different browsers doing this project. I just gave up on Firefox because I ran out of ideas to try. It wasn't due to lack of trying.

Anyway, someone made a suggestion of what to try in another comment, and turns out it was really easy, so now it's fixed. Firefox just does software blurring which is super slow and so I just had to turn that off entirely for Firefox. So Firefox performance is now okay enough, although still not quite like Chrome.