In addition, Google is still run disorganized-bag-of-cats management style and YouTube is so indpendent from the mothership they're almost their own company.
Conspiracy is unlikely purely because Neal Mohan is empowered to tell the Chrome team to pound sand and will do so if he thinks they'd make a call that would damage YouTube's numbers.
Instead of just "stop using it" (pay isn't actually an option here, people who are paying are still getting the delay), let's force them to comply with reasonable antitrust regulation under threat of fines. Or preferably, break them up, youtube shouldn't be part of google and neither should chrome.
Not to mention, if performance with YouTube is slow, there's no clue for users that Firefox is the problem. There's no banner telling you "for faster YouTube performance use Chrome". And it's extremely unlikely that your average user is going to try to compare with Chrome, or even the thought occurs to them. They probably think their ISP just got worse or something.
If this were an actual mechanism to try to get users to switch, it would be an idiotic one.
Youtube does experiments based on user-agents. I think this is well known and if not, a former Googler just let you know.
In any case, for those who are complaining, it's their website. Either pay or stop using it?