Delegating that control is, in effect, a form of collective bargaining. Whereas Epic could convince individual users to accept whatever terms of use they wanted

Delegating that control is, in effect, a form of collective bargaining. Whereas Epic could convince individual users to accept whatever terms of use they wanted to impose, effectively Apple collectively bargains for all those users. That means that, if you like the way Apple negotiates and are comfortable with the trade offs they make, you have much more leverage than if you were negotiating as an individual.