Is that network worth 30% of the selling price in all cases? Does "one size fits all" really apply here. As an example, it's already been pointed out in plenty of places that Amazon doesn't have 30% to give to Apple, even if it wanted to. They are locked in to agreements with publishers that demand a 70% cut.
I can identify with them as well. I work with a good friend in the publishing market who has a product that they want to bring to iOS. His product facilitates the delivery of interactive book content from publishers and distributors to schools and libraries. Neither the publishers, distributors, nor the schools seem to have even the beginning of an idea on how to solve the problem themselves, yet his business model would be wholly incompatible with the Apple pricing model. As a facilitator, his company only makes a couple of dollars on the sale of each SKU. I just sat across the table from him at lunch today and recommended that he stay as far from the Apple App Store as possible. Going back to the table and requesting an additional 30% from publishers and distributors would get him laughed out of the room.
The greater point is that by applying a fixed 30% fee to all in-app purchases, Apple is excluding many different business models that might otherwise be developed on their platform. I know they have their reasons, and Apple is famous for disregarding edge-cases in favor of simplicity for the larger market, but there are a lot of models that flatly don't fit this fee structure. Anyone whose margin is less than 30% simply cannot move product through the Apple App Store.
Businesses stuck in this position have to decide which will be more costly and difficult: retooling their business model to accommodate an additional 30% margin, or avoiding the Apple ecosystem altogether and finding another way to reach their market. In my opinion, an extra 30% of margin is not easy to find in any business, much less the cut-throat content publishing space.