To me it seems anti-competitive to disallow streaming services to use their own payment model. I expect a lawsuit to come from this and within the next two years either Spotify will be Daenerys, Breaker of Chains or Erlich Bachman, Waster of Cash. It seems like Apple have created a monopoly within their own ecosystem. Whether their ecosystem is too big to be monopolised will be up to the lawyers as regulations are pu…
There's no such thing as a "monopoly within an ecosystem".
Either you cover the majority of the full market (not of your market), and you're a monopoly, or you don't.
If you don't, then within your own platforms, shops, and premises it can be your way or the highway.
Nobody has a right to tell you what to sell or not sell, and how much to charge for things in your own shop -- kind of like with a physical shop. It's not Apple wanting Spotify to be sold through their platform/store and asking them -- it's Spotify wanting to take part in Apple's marketplace.