> If I charge 30% to host foodcarts at my concert event, cart owners will agree only if it's a good deal.
They agree because it's the best deal. In your hypothetical and the case of IAPs, it's the best deal because it's the only deal. When the options are make no money and make a little money, you're going to take what little you can get. That by no means makes it good.
Devs have no choice. Users are caught in an Apple/Google duopoly and both app stores charge 30%. Devs can either pay their 30% or give up on IAP revenue as a whole.
Dealing with license management and account access and payment processing and chargebacks and international tax compliance and everything else I am not thinking of after only five seconds is actually a lot of work. Apple has a lot of revenue from the App Store, but almost no profit: it is something they run and have weird business model restrictions on to maintain device lock-in for users, not something that makes them much profit. In fact, Apple has often reported in public earning calls that the App Store mostly breaks even, and a judge reviewing Google's finances showed that they were losing money on the Android Market.
I run an app-store-like service myself with the same 70% split (which is a more honest way of describing the "30%") that has no forced restrictions (as you can always sidestep it and still distribute your products via my services), and vendors have often even shut down their own payment processing once trying mine as it is just so much easier: being able to concentrate on building your own applications rather than spending time on distribution is actually valuable.
Again: the reason Apple wants payments to go through their wallets and they want licenses for apps to be managed by their store and to control the device licensing model is to maintain platform lock-in for users. It is really important to them that when you buy your paltry $30 in apps--where even if Apple made all of the "30%" they would only net under $10--that that "investment" doesn't make you think twice about plunking down $600 on a new iPhone, where estimates have been made that Apple has a nearly 50% profit margin.
To make this work Apple needs to maintain all of this ludicrous platform control, as otherwise your custom licensing model is obviously going to support stuff like users getting discounts if not entirely free copies of your app for Android if they just bought it for iOS or charging upgrade fees for users who switch to the latest generation of device. I honestly don't believe that given their intense desire to maintain this control--which I will argue is the real problem here--that the 30% just falls out as a reasonable charge for what they are providing (in some cases whether you want the service or not, such as the app review process).
They agree because it's the best deal. In your hypothetical and the case of IAPs, it's the best deal because it's the only deal. When the options are make no money and make a little money, you're going to take what little you can get. That by no means makes it good.
Devs have no choice. Users are caught in an Apple/Google duopoly and both app stores charge 30%. Devs can either pay their 30% or give up on IAP revenue as a whole.