I think the difference is that when you open Spotify, you expect a complete or almost complete catalogue. People have existing artists that they really want to hear. That puts Spotify in a tough negotiating position as they have to license more or less everything.

When you open Netflix, you just want to watch something interesting within some category. That opens the door to Netflix creating its own content and puts them in a much better negotiating position vis-a-vis Hollywood. They don't need to license everything.