As in, to continue with the game console analogy, you must have at least one license to a powerful engine (like Unreal Engine with a 5% fee) to develop efficiently.
Do you actually save 5% (assuming PS is 30%) by developing for the Apple ecosystem? (Assuming Metal is comparable to Unreal)
Probably not - assuming you're being smart and targeting multiple platforms, you're still going to be using Unreal/Unity. And even if you're only targeting the Mac, Unreal/Unity bring a lot more than rendering to the table, so you're probably still using either of them, all with a commercial license.
And unless you're doing distribution yourself, anywhere you put your game will take a percentage, pretty much all around 30%. Some places like itch.io let you define how much they take, but no one really uses itch.io for anything bigger than an indie game.
Depends, plenty of indies are doing alright with Apple's own gaming frameworks.