But there's actual competition underlying this fee structure, since the users can easily move from Amazon to e.g. eBay or really anywhere else in search of some item that they want. The only lock-in that Amazon might have on them is Prime membership, which the users have to actively opt into.
Whereas Apple could start charging 50% tomorrow and still have all the major apps in the store because of their market dominance position combined with ecosystem lock-in and walled garden.
So we do sell on other e-commerce platforms and you’re never gonna guess what their fee structures are.
(Basically the same as Amazon’s)