It puzzles me that some people still think 30% is a reasonable cut for any kind of online store.

Imagine you're 3 guys / girls and working on an app / game / .. whatever and one person only does "distribution" of the final asset. You are working one / two years or more on it, and one person only checks / verifies the final asset and organizes hosting. How is this in any way justified? And the days that person made any marketing / visibility are long gone. I think more "fair" is something like 5%, more in the line of what a payment processor does. Which probably, at this point does more than.