Take

Without our apps, the iPhone has little value to most of its customers today.

[..]

[I]n the common case — and for most app installations, the much more common case — of searching for a specific app by name or following a link or ad based on its developer’s own marketing or reputation, Apple has served no meaningful role in the customer acquisition and “deserves” nothing more from the transaction than what a CDN and commodity credit-card processor would charge.

The idea that the App Store is responsible for most customers of any reasonably well-known app is a fantasy.

I pulled myself out of this in 2008 because I hate the idea of the App Store and have scarcely been able to shut up about it since. It's easy, or at least possible, to imagine that my unending grenades are just sour grapes or fantasies unmoored from reality. Marco ships Overcast, one of the most popular podcast apps in the world.

This is what it comes down to. Epic's inability to use another payment processor is just a symptom of the same disease. Beyond the mobility of huge companies, it affects the everyday lives of developers and customers as being users – this is where we live, and Apple are not being reasonable stewards of this community.