One can hardly emphasize this point enough. iOS users buy shit. The process of buying stuff on iOS is easy, easy, easy. It's unusual for it to be more than just

One can hardly emphasize this point enough. iOS users buy shit. The process of buying stuff on iOS is easy, easy, easy. It's unusual for it to be more than just the password prompt and the tiny pause for verification. When buying things is that easy, people buy more, and developers genuinely do make it up on volume. That's why the iOS App Store does so well - it has a solid track record of making money for developers. That's why developers in the iOS App Store put up with the restrictions it imposes - because you can make good money there.