I don't really understand the argument. The App Store can be a service to both developers and consumers.
That's typically what a store is. Product manufacturers accept that they will sell more of their product in stores, enough to make up for the margin added by the retailer, vs direct sales. Consumers accept to pay more the convenience.
It's only indirectly true that the App Store is a service to developers.
It's a very straightforward argument.
Apple has the App Store in order to keep consumers. That it helps developers is a side benefit. Apple would drop the store if didn't retain consumers on the platforms.
