If you look at the recommended content for most major services, they give a lot of space to "stuff you've consumed before". Anecdotally, this is true of Netflix (which tends to rank already-seen content below it's own-brand shows but above other third-party stuff); and it's especially true of Spotify, which is constantly pushing me (in a real variety of ways) mostly music that I've already listened to.
I think it's likely that, music video or not, most users on YouTube are watching the same videos over and over again - hence why the algorithm tries to hard to cater to those users.
From a cynical perspective, such an algorithm is also a "safe" bet - if you won't even binge videos YouTube knows you like (because you've seen them), it will probably be much harder to get you to watch lots of videos you might like. Users who like to see the same stuff over and over are probably giving the best return on YouTube algorithmic investment, and they might even be YouTube's most valuable users outside of content creators.