One of the many problems with machine learning, and using it for recommendations, is that it completely ignores how humans think and behave. Just because I watch a few videos of a certain type today, and actively seek them out, doesn't mean that I want to see similar videos again next week. Maybe I was just in the mood for that type of content today, tomorrow may be something completely different.

That being said, YouTubes recommendation algorithm is mostly garbage. I don't believe it has any insight into the actual content or quality of the videos it recommends.