We have a couple apps and there really is no "discovery" through the App Store. You have to pay for ads, whether in the stores directly or in the many ad networks that put you in other apps or other advertising. Unless you're already at the top of the lists (because of your off-store brand), or you win the lottery in the game of getting featured, the App Store doesn't drive new users.
For the majority of apps, the App Store doesn't provide discovery. It provides a nearly frictionless delivery and purchase interface. That's worth something, but not 30% off the top. That's worth a premium on top of processing fees, like X cents per transaction and Y% of the transaction, where Y < 6, I think.
Edit: I should say, I don't think there's any way this is going to happen. It would take an anti-trust action to make any difference, but that's not likely to happen.
For the majority of apps, the App Store doesn't provide discovery. It provides a nearly frictionless delivery and purchase interface. That's worth something, but not 30% off the top. That's worth a premium on top of processing fees, like X cents per transaction and Y% of the transaction, where Y < 6, I think.
Edit: I should say, I don't think there's any way this is going to happen. It would take an anti-trust action to make any difference, but that's not likely to happen.