This touches on one of the big issues with the agency model, Apple's 30% cut of IAP, and the rule requiring all digital goods purchases go Apple IAP made Apple

This touches on one of the big issues with the agency model, Apple's 30% cut of IAP, and the rule requiring all digital goods purchases go Apple IAP made Apple the only bookstore on apple iDevices, outside the browser. IMHO, when the iPhone was the leading smartphone in the US, that wasn't a walled garden, that was a market leader leveraging that power to take another market in an anti-competitive way.