This really is a curious argument from both sides.
On the one had Epic has a point. 30% is a massive amount to be giving to another party (when you have the infrastructure in place to take payments yourself). The way Apple applies App Store rules is also shockingly inconsistent with different types of content and let's not forget the special "exception" that allows for Amazon's Prime app. Apple can quite literally make up the rules as they go along.
However I've never got this notion that you MUST be in the App Store and play by their rules. Apple's wording with the Hey issue was very telling:
Apple considers iPhone users Apple customers and that's the end of it. Developers are welcome to a free ride accessing THEIR customers if the rules are followed.
So if you don't like that your platform or App is based around the customers of another company it's simple. Leave. If enough developers leave then the iOS ecosystem will die a very quick death (granted, it would make Android the hyper-dominant platform...). Or Apple will come grovelling back to gain App support 🤷♂️
Ultimately Epic went out of their way plotting to humiliate Apple which is fine but they should've known the end result would be getting cut off from everything Apple. Or "You hate our platform so much we'll help you get off it by requiring you to follow every sentence of our agreement". Apple don't owe Epic anything. What is slowly panning out is that Epic needs access to Apple platforms (thanks to Unreal Engine) more than Apple needs Epic. Apple would prefer developers to code exclusively within the Apple ecosystem and toolset anyway.
TL;DR - Know what you're getting into with closed ecosystems and if you don't like it there are plenty of open ones.
The problem with a closed ecosystem is that as it becomes larger and more encompassing in society, it becomes difficult for new competitors to enter. In vertically integrated markets, there's often only a handful of giants.
In the smartphone market (which I would argue is essential to modern life today) if you don't like Apple's ecosystem, the only other choice is Google's. That's not a "plenty" of them.