10 years ago the most popular 100 videos on YouTube were all pop music videos. Justin Bieber had 3 of the top 10.

The youtube algorithm has been personalized for much more than 10 years and has never prioritized any kind of lectures or artful films over anything else it thinks a viewer will watch. You're asking for them to bring back an era that never existed.

If you're not getting those sorts of recommendations it's because you ddon't actually watch that kind of content, or you're removing your history.