It turns out that if you try to take a 30% cut from publishers, publishers will not want to work with you. That's what Apple found out after most major publishers balked at their draconic rules for how the could sign up subscribers on the iPad. But Apple's changed it's ways.
Originally, the rules stated that "app owners offering subscriptions outside of App Store were required to sell equivalent, in-app services at the 'same price or less than it is offered outside the app,' while giving a 30 percent cut to Cupertino."
Now, publishers can price in-app subscriptions however they like, allowing them to up the rates to make up for that fat Apple share. They can also exclusively sell subscriptions outside the app, which will allow them to cut Apple out altogether.
It seems like a fair compromise between two groups who really can benefit each other in a lot of ways, provided they can play nice.