This is the opposite of what I was expecting to read. The developers with the lowest income receive the most benefit from Apple as they presumably do not have a large, existing marketing list to convert to sales and so rely on App Store discovery (what exists of it.) If anyone should pay different rates, it should be the more successful developers who convert to an expensive premium developer account subscription. This is the model used by Ebay, Etsy, Shopify, and a lot of other markets.