Don't worry, they'll just put a new clause in the agreement that says you can't charge more to iOS users than non-iOS users. Stores won't raise their prices 30% for all users or they'll go out of business. So they'll either give Apple their 30% or not sell through iOS devices at all. Not necessarily an easy choice, especially if you're already established with millions of iOS users.

That 30% will not come out of your pocket; it will come out of the provider's pocket. Apple will see to that, don't worry.

Apple will amend that agreement as many times as they need to in order to maximize the benefit to them. Let's not kid ourselves and think the benefit is for their users. I think we're all wise to that one by now.