> ... Apple does exactly zero things for me and still wants 30% ...
I'll bite. The Romans, err I mean Apple have done nothing, except at least these:
* Maintains a user database including authentication, plus all the support costs (lost password support is very high)
* Payment handling (you dismiss it, but no one does it for free) including keeping up with tax authorities and legal systems in much of the world
* Almost unlimited (re)downloads for users to a reasonable number of devices. Bandwidth is cheap but not free.
* Backup and restore for application data. (You may not use it, but that functionality is available to apps without extra fees.)
* A curated walled garden including a review process. I'm sure your app is fine, but Apple keeping the dregs out and avoiding the place turning into a cesspool means users can be more confident about the apps and that halo effect helps all apps in the store.
* Mechanisms to extend your app such as IAP, and an advertising solution etc
* Access to a large user base, with reasonably fair rules that everyone has play by
* They make all the above work together
The case can be made that the benefits used vary by app, but in aggregate it isn't an unreasonable amount for them to charge. It is worth noting that competitors haven't done anything substantially different.