I don't believe you can say that without adequately providing evidence and financial breakdowns. Not saying you're wrong, but given that developers even in the EU where alternative app markets are allowed still publish to the apple app store, I think that it's likely more fair than you realize. The cost to do all of what they provide for a $100/yr dev license + 30% pro-bono is immense. Even the least used applications with the smallest budgets receive state of the art infrastructure, toolkits, and security review as well as a bevy of other apple provided resources. It's the same for other marketplaces as well. Steam for example provides marketing, development guidance, server hosting, and a wide variety of other non-trivial non-free to provide services for their share of the cut.