And creating a multiplatform coherent, attractive, and performant UI on top of an infinite catalog of music, with recommendations, shareable playlists, "radio stations", and on and on - is no small feat. Apple shows no capacity for doing this any time soon. Heck even Spotify is barely holding it together, and this is their entire business.
Apple might pre-install their app on iphones, but they don't support even 10% of the devices Spotify does.