Great points. Interestingly, the one thing I don't use YouTube Music for is music videos; I don't have anything against them, it's just that most often I'm not looking at my screen when I'm listening (I'm either using head phones/ear buds or am connected to speakers). I wondered how much of a problem that might be at first but I just keep the player in audio only mode.
Part of the YouTube Music service also gives me ad-free YouTube videos though so, when I am using my screen to watch videos, I definitely get the full benefit.
I can't comment on how the recommendation engine compares to Spotify overall but the YouTube Music engine is definitely faster to get my preferences. Spotify's Discover Weekly specifically says that it needs to learn your tastes "for a few weeks" but, with YouTube Music, it took about an hour of set up and "liking" songs and pieces of music.
I really like your mention of the "old school music economy" which I was obviously invested in prior to streaming. For me though, that is where creating playlists was so important, because I didn't like it when I'd start humming the start of the next album track in the gap between tracks. Playlists were great for mixing things up.