But it is not. The total revenue projected this year for App Store is roughly $50B. I would bet $1000 the average credit card processing fees world wide for is lowered than 2%. With China, EU, AUS, and Japan all has much lower cap on it. The whole yearly revenue for the one of the largest CDN Akamai is only $2.5B. Not only s Apple's data requirement less than Akamai, they now also operate their CDN. There is absolutely no way the Apps Store storage and delivery cost more than 500M to operate, even if Apple were using Akamai.

Given the economy scale advantage, Apple are likely to break even at 4%. So even at say a 5% running cost, Apple is making 25% Net Profits. Giving them 10% of App Store revenue is already a 50% margin business.

Like I said again and again, the physical world roughly the same or more than that. But it has a bigger operational expenses and rent. We cant argue with property prices or Rent, it is the fundamental of how our modern society creates a thing call money. But in a non physical world, Apple and Google needs to demonstrate how this 30% is worth while, rather than pure money grabbing. Google has a much better excuses because its App Store profits will be needed to continue and fund the development of Android Operating System.