>Of course, this ignores the issue of Google revenue. Advertisers targeted you, target you based on the videos you've watched. So there's that too. Google recommends videos for which it has relevant advertisers.

I think this is exactly the problem.

Contrast this with the recommendations I get from my paid spotify account where I don't get ads: It's absolutely Excellent. Seriously, whoever worked on Spotify's recommender system algo deserves a huge pat on the back. They have the best recommender I've encountered anywhere on the net, and I pay a lot of attention to recommenders. It's just light years ahead of everyone else.