This move makes totally sense if you consider that Apple is trying to control the streaming market the same way it controlled the download to own one. I'm sure the labels will do whatever they can to avoid it.
Spotify is a (big) thorn in Hook's foot and Ek would die rather than sell Spotify.
That also explains why Apple is not releasing the 30% tax for music streaming and why Spotify released an app with its own payment system to grab attention. It's war.