> The service fee for each developer will be 15% for the first $1M (USD) of earnings you make each year when you sell digital goods or services. *
* https://support.google.com/googleplay/android-developer/answ...
This is probably an indication that Google/Apple make most of their App Store profits from a small number of big developers.
Sure, in those cases you consume more resources, but those are probably negligible compared to the increase in price. The reality is that they charge you more because you make more money from the service, hence you are willing to pay.
It's not precisely the same, obviously. For one, you can chose the services you want, while you must go through Apple's App Store. And since they don't charge a percentage of revenue but charge for resources, you don't see the correlation.
But the final effect is the same. The more money you make, the more you pay.
That said, a lot of higher tier offerings in SaaS differentiate themselves by SLAs, Support, assigned CSM, consulting time, etc. Those are cheap-iah to deliver when everything goes well but can cost a lot when there are problems.
It gives a price cut to the most number of people, but requires Apple to give the least amount of money away. This gives them really good press, and helps them to deal with their "image issues" that they have at the moment. Basically a win win.