Thank you. Seriously. It seems that people are the CFOs at Apple and know exactly how much it costs to run the App Store. Should we cut it down to 5% but make the Apple Developer Platform $1,000+ a year instead of $99? As you said, free apps still need the infrastructure and support. Does $99 a year cover all of that? Who knows. I certainly don't. And I don't think anyone here does either. It costs an awful lot to not only host something that gets downloaded millions of times, but to do it at a CDN level costs even more (I pay my CacheFLY bill and I don't have that many downloads and it gets expensive).
People do not understand infrastructure. I was a Director of Infrastructure at a company for some time. I know how much it costs from the servers, storage, network, server rack space (or with Apple, probably property costs since they probably have their own building) and so on.