An acceptable profit margin would be based on actual costs, not a static 30% which means paid apps are subsidizing free apps or apps like Netflix and Amazon that do not take payment on iOS. Charge based on bandwidth/downloads, not on who is using their payment processor.
> Charge based on bandwidth/downloads, not on who is using their payment processor.
This obviously doesn't tell the whole story either. Some apps provide utility to the end user but don't monetize well. Those apps are valuable to have as a way to drive people to use app store, and keep developers educated.
