Music services still recommend music by answering, "what do other people who listen to the stuff you listen to also listen to?" This Balkanizes our libraries, because it fails to cross cultural and regional boundaries.
Suppose two tracks, one in Japanese and one in English, are great for extremely similar reasons pertaining to how they actually sound. Spotify and Apple Music would would never recommend one for the other. It seems like high time that algorithms drew from analyses of music’s intrinsic qualities: sound, BPM, lyrical sentiment, etc.