I can ask you the same question...
As we keep telling you and Marksman over and over, In-App Purchases only provides payment processing. When paying the 30% cut of In-App Purchases, all you're paying for is the payment processing. This is even stated in the Apple documentation.
Apple has a service : Payment processing. They call it In-App Purchases. As a developer/Apple customer, I am paying 30% for this payment processing.
Any business related expenses for this service are not my business nor do I care about it. I shop around for payment processors and Apple is the most overpriced one around. Why does Apple feel they need to charge more than everyone else for the same service, Payment Processing ?
This is not a problem in and of itself. The problem is that I am forced to used them if I even want to hint at the possibility of purchasing stuff in my own app I wrote myself and paid 99$ to get hosted, as per their App hosting/selling service on the App Store. I already paid in full for this service, why do I suddenly absolutely need to use another service of theirs ? One that is overpriced for what it is no less.