This is the key problem when a market-maker is also a market participant. When the same entity setting the market rules, deciding who is violating them, and collecting the market data is also an active competitor against everyone else in that market.

It's not a fair playing field. Apple knows that, but pretends that it is.

I say it's a problem, but I don't have a solution. It's hard to say "Apple can't make apps for the iPhone". Or "Amazon can't sell stuff on Amazon". Or "Google can't by ad space on Google Ads".

There clearly needs to be some sort of laws to restrict these kinds of behaviours, to encourage a diverse and open economy rather than rigged games.