If Apple charged all developers fairly you’d have a point. They don’t charge Netflix, or any app that is ad driven like YouTube…If Apple only charged fees on the initial download, EVERY app would just become free and prompt you to make an in-app purchase before the app would be useable. It'd be a very easy loophole to exploit, charging the commission wether the developer wants their user to pay up front or via IAPs given the developer flexibility based on what their app does/what makes sense for the user AND ensures Apple gets paid.