Even Nintendo allows you to buy Nintendo games at a store not owned by Nintendo. I'm not sure how the commissions break down but you can still buy digital Nintendo games at other stores like Amazon, Humble Bundle, Wal-mart etc. And of course physical options are still a thing and Nintendo doesn't see a dime if I buy game off some dude on Craigslist. I can't get anything off the Apple App Store without going through Apple.

Apple doesn't make most of their revenue from selling games. It's selling microtransactions in games. They are basically skimming off a few thousand digital casinos at this point.