Ads on YouTube have become annoying enough to make me hesitate before following a link to the site. I really wonder how much further they can push this without either driving users to using ad blockers or creators to upload to other platforms. Unfortunately, I suspect the answer is "pretty long"...
I'm not so sure.
I'm only a casual viewer of YouTube. I don't engage in any of the account-based stuff, just watch the occasional video hosted there. But even in the content I've seen, it's clear that the semi-pro creators -- the kind of people using schemes like Patreon these days, and maybe placements as they get more successful -- are very aware of how they come across.
In particular, they might already be hosting their content on multiple services, particularly those who livestream events of whatever kind, where they might stream on Twitch one day and YT the next. Those who are successful enough to make significant money from their videos are well aware of anything affecting their video quality, audience numbers, and ultimately revenue.
I doubt many of them will have any great loyalty to YT if it becomes too awkward or expensive, and I'm sure many of them already have accounts on other services and the bulk of their followers would know where else to find them if YT shut down their accounts overnight.