That's one way of looking at it. Another is that it protects Apple from having their users find out that 30% of what they're paying gets nowhere near the person they think is getting all the money.
I do not believe keeping the price equal to other helps the consumer, it's simply Apple keeping developers from charging the 30% straight to the consumer. I believe it would be interesting if they let this restriction slide. Perhaps the advantage of simple purchasing makes up for an increase in price. Convenience is also worth something, as supermarkets have found out.
What? It's specifically set up to protect Apple's cut of 30% and to prevent other app stores from charging less.
Lets say you price a service at $14/mo. Apple takes 30% so you price it at $20/mo. Apple takes $6/mo. Windows 8 ap store takes zero if you roll your own in app mechanism, but you can't charge Windows 8 users only $14/mo. You have to charge them $20/mo if you want to stay in the iOS App store.
How is Windows 8 users being forced to pay $20/mo instead of receiving a benefit from their platform competing, protect Apple customers?
Surely in a world where the network effect rules and the stakes (the global marketplace) are so high, we shouldn't allow networks to entrench themselves too easily? Else we'd just have a behemoth in each sector, probably the same few companies even.