I'd be surprised if they do this, because YouTube is fundamentally a data gathering-and-selling company, and you get plenty of data from people who use ad-blockers. And ad-blockers are only growing in popularity.

Nevertheless, if YouTube did prevent me from watching a meaningful amount of videos, that would be good for me, because I watch too many YouTube videos as it is. Moreover, it would provide significant motivation for me to make that YouTube client I've been thinking about for months. It would download videos from specific channels, and I could watch/search them locally. That way, YouTube gets less data, and I get to waste less time watching YouTube.

Side note: if you are looking for an ad-blocker, I strongly recommend uBlock Origin. uBO does more than just ad-blocking, such as privacy stuff and to block elements of pages (e.g. the annoying banners that say "please consent to biscuits" or whatever they are calling it nowadays).