Unless "everyone" also includes Apple Music, then it's anti-competitive.
Apple could charge themselves the 30% App Store fee for Apple Music, demonstrating that the App Store is a fair marketplace that doesn't artificially advantage Apple's own services. It would then be incumbent on Apple to prove that Apple Music is priced fairly, rather than being deliberately operated at a loss to squeeze other streaming music services out of the market.
It's somewhat similar to net neutrality proposals. AT&T doesn't have a monopoly as an ISP. However, if AT&T starts/acquires a video streaming service, they should not give unfair advantages to their own service because they want to compete with Netflix.
What does it change ? Nothing.
It’s on multiple platforms, it’s tied to Beats, it has a relationship with iTunes Store, there is advertising involved etc. So there could be multiple licensing and revenue sharing deals that mean Apple Music is not running at a loss.
In fact I think it’s likely than you’re wrong.
Interesting, so Spotify could pay nearly the same simply by paying the 30% to artists instead of Apple.
And of course, those 37 might already be partly paid by Spotify anyway.