Yep. The difference is that even though your choice of payment network is still relatively limited, there at least is some genuine competition on price. The Android/iOS duopoly seems to have become stuck at a particularly bad Nash equilibrium. 30% would never survive in a competitive market.
I'm doubtful competition mechanics would work to reduce the app store cut even if it wasn't equal between Android and iOS. If Google were to cut its rate to 10%, then what? App publishers aren't going to stop publishing on iOS. Even if cross-platform apps changed their pricing schemes to be cheaper on Android than iOS, I doubt many iOS users would be particularly put off by the extra 20 points in the cost of their apps.
The point is that the market is not competitive. Tweaking rates doesn’t suddenly make the market competitive.
For just one tiny example, consider web browsers—iOS doesn’t even allow browser engines aside than WebKit. Now compare this situation with that of desktop operating systems, which are still not a super competitive market by any means, but where the fact that Windows users could install browsers other than IE meant that web browsers became a competitive market, leading directly to the increasing capabilities of web apps, leading in turn to the possibility of Google’s office products even existing, making office software more competitive, and that in turn making Chromebooks feasible, which leads all the way back to making desktop operating systems more competitive.
You can’t consider the effects of tweaking one number and conclude that a market would be changed/unchanged by competition—these sorts of things are extremely interdependent.
