> Sure it is - because Apps are curated, you can charge more for them.
That is not a sure thing. Having a wealthier customer base could be as much or even bigger a reason for the higher revenue. And curated apps still have to compete with each other.
> If there are free alternatives available everywhere, people will be less likely to pay.
If this were really the case, it would actually be an argument for increased competition because it would be better for the consumers. However, I do not think that it is true because almost 93% of apps in the App Store are already free.[1] So the 100% revenue difference probably would not disappear. And free apps would have to follow Apple's privacy rules, as they do now.
> So the App Store is a net benefit - what, exactly, is the problem?
Of course it is a net benefit. Even if overall fees were 99%, it would still be a net benefit to both consumers and developers because retaining 1% is still better than nothing for developers, and having a software repository is very valuable for users. No-one is suggesting shutting down the App Store. What is being suggested is for Apple to allow other firms to compete against it, because they control almost two-thirds of the market by revenue and can dictate the terms to the participants.
> There is no demonstrable harm.
That is for Epic to prove. They would try to demonstrate that they suffered harm after violating App Store terms by offering a competing payment method, and that it is anti-competitive for Apple to eject Epic's app, given its market position. Regulators would also have their own methods of determining whether harm occurred.
1. https://www.statista.com/statistics/1020996/distribution-of-...