Of course. And that fee is collected when developers join Apple's Developer Program.
Join the Apple Developer Program to reach customers around the world on the App Store for iPhone, iPad, Mac, Apple Watch, and Apple TV. Membership includes all the tools, resources, and support you need to develop and distribute apps, including access to beta software, app services, testing tools, app analytics, and more.
What products and services from Apple is Epic using that the Apple Developer Program fee doesn't cover?
The payment processing? Nope. Game server and other hosting costs? Nope.
What is there?
Yes, but just because an agreement has been signed doesn't mean it's legal.
Take non-compete agreements as an example.