They'll launch their apps if/when Apple Vision Pro gains more traction.

YouTube is probably the biggest one missing, but it works just as well via a browser. Netflix has a lot of stuff but it's far from the only horse in town nowadays (and again, it should work fine via Safari). And Spotify is easily replaceable, as song availability is 99% identical between pretty much all music streaming services. People who want a Vision Pro will get it regardless of whether Spotify is available, and they'll likely just switch to Apple Music if they want to listen to music with the headset.