I get your point. I got your point the first time. But there are a lot of "ifs" in your hypothesis.
Meanwhile Apple is not attempting to undercut Spotify in the retail space. And they are paying artists substantially more than Spotify for the music so they're clearly not attempting to run a more profitable business.
There is no IF, all Apple apps have unfair advantages, not only financial but I also mentioned access to private APIs.
The user looses when there is not enough competition, like you get stuck with a worse browser (but in this case this may be a deliberate thing to protect the app store)
Meanwhile Apple is not attempting to undercut Spotify in the retail space. And they are paying artists substantially more than Spotify for the music so they're clearly not attempting to run a more profitable business.