Amazon's app store works differently, from what I remember - Amazon buys X copies of an app and sells it at whatever price they want. I have no idea how that works for DL content. IMO that's a worse model for app developers, but I guess it works for those on Amazon's app store.
It's a long, long time since I was involved in selling software, and then only on a cottage industry scale, but one deal I encountered from larger distributors was that you
gave them X units and when they sold one of those they'd buy a replacement (at a hefty discount). Then there were small stores with a customer who'd read
our publicity and walked into the store and ordered it by name... and expected a 50% discount (probably on 30 day terms) for doing nothing.
The 30% markup (plus a developer subscription that seems to be missing a few 0s by my experience) on the Apple store - which gets you into their online store and covers payment processing - always struck me as a freaking bargain.
The downside is that you could invest a lot of money in writing an iOS App and then have no way of selling it if Apple rejected it for unfair reasons (e.g. they thought it competed with an Apple product) - so if Apple had dropped Fortnite for no adequately explored reasons shortly after adding a new
Battle Royale-themed game to Apple Arcade then
maybe we might have a monopoly abuse case... but the same applies to pretty much any of the major games consoles, and Apple doesn't have anything
resembling a monopoly on mobile devices, let alone computer gaming in general... They're
allowed to have a monopoly on iPhones...
As I see it, the Apple/Epic thing is about using the "free-to-pay" scam to cut software retailers out of the loop (while also sticking users with rubbish games that are purely designed to push in-app-purchases). The logic goes a bit like this:
King Camp Gillette: Howdy, shopkeeper. I have this exciting new business model where I give away razors and then charge a fortune for the blades. How'd you like to be part of it?
Shopkeeper: Sure seems like a license to print money, I'm in. What's your wholesale price for three gross of blades?
King Camp Gillette: Heck, no - you don't get to sell the blades. I want you to give away the razors!*
Shopkeeper: How many fingers am I holding up?
(* Although a good shopkeeper will make money off all those people coming into the shop to pick up their free razor - doesn't work so well online).
The only place where Apple
might be on a sticky wicket is if they favour Apple Music/Apple TV etc. over competing services by bundling them with iDevices (i.e. using their position in one market to gain an advantage in a totally different one). That's probably why they've reputedly given better terms to Spotify, Netflix etc... but those are
real services where the whole value is in the constantly updated content, not fake services that are just a ruse to make you rent your software.