This is the biggest confusion. You're not paying 30% for Apple to process your payments -- you're paying 3% for that, apparently. Not really a surprise since that's what every other CC processor charges but now we know. The rest is a sales commission, always has been. If you read any of the documents for the Apple/Epic lawsuit you can see exactly that. You want to reach iOS users and sell to them on Apple's land, that's the price.

You wanna sell stuff to players in your Xbox game, 30%. You wanna sell stuff to players in your Playstation game, 30%. The service they're selling is stalls in their market that gets a lot of foot traffic.