Depends on what you define as their game store. I can purchase a game that is playable on the xbox from anywhere that sells a copy. One of these places is the digital store that comes with the xbox. But I can also go to cd-keys, or amazon and buy a copy there that will still work on an xbox.
That's a licensing fee and separate to the discussion about market control. As it stands (although this is starting to change) a developer can sell the game through a variety of different avenues (online, brick and mortar, the xbox store), these avenues may have different prices associated and drive where the consumer makes their purchase.
That is the relevant comparison here, if Epic want to provide Fortnite on iOS they HAVE to use the app store and associated requirements. If they want to provide it on XBox, they pay a licensing cost for the proprietary tech they leverage from Microsoft. But they can choose to sell the game on Amazon if they want.
Even if they sell the game on Amazon, they still pay Microsoft a royalty for each game sold. Whether you want to call it a "licensing fee" or a "Microsoft tax" seems like a matter of semantics. Also keep in mind that their publisher agreement with Microsoft gives Microsoft approval rights over the game itself, marketing materials, and even packaging. And if they sell virtual goods in the Xbox version of the game they have to go through the Xbox store and pay Microsoft 30% of that.
The amount of control console manufacturers exert over the games allowed on their platform is not dissimilar to the Apple and its App Store.
I don't think you realize the permissions game makers need to even sell a CD that works on xbox. If that CD is not signed off on by microsoft - total control -> it's not going to work in your console - period. And the irony - EVEN IF microsoft does not market / distribute or accept payment for the game (Apple does all of this) I can guarantee you Microsoft (and sony) get a cut.
Look at the PS5: the ability to put a disk in is a legacy that's clearly going away by Sony making it an option you'll have to pay extra for. The entry level model is digital only, for better or worse.
That's definitely true, and as they move away from physical media more scrutiny of what they are doing is required. But as it stands this isn't yet an issue for game consoles
