Appstore model is as old as civilization - middle man reselling stuff. Some middle mans are more effective than others, and true, Apple is one of them. But that doesn't change characterization of the relationship. They don't pay developers for their service, they resell their stuff, while keeping hefty profit margins.
The entire mobile app market was not even one hundredth the size of the App Store before it was created.
The walled garden Apple created made safest and easiest app purchase environment ever, which is why it attracts the highest spending by app customers and highest spending app customers.
If Apple had taken the Google play route that $35B a year would be closer to $4B a year.
Why is this always added as if it's relevant? If I'm selling an app on both stores I care about how much money I can make in total, how many Android phones have been sold globally is just trivia.
If you don’t like the ratio, just say App Store sales are 50% higher than Android.
That $35B didn’t exist until Apple created the iPhone and built its walled garden.