> this seems obscene
This is why I never cared about the 30% take: it was combining all the costs you'd have anyway into one simple number. People just acted like those things were all free just because Apple wasn't explicitly listing them.
Could you optimise your expenses better by splitting them?
Probably.
And that may even be worth forcing the issue from a competitive PoV, because it means some customers will be effectively subsidising others: A weekly updated 2 gigabyte app that's free in the app store gets its bandwidth paid for in part by a 30 Mb app that charges a $10 monthly subscription and gets an update every 3 months.
But even then, companies are expected to make profits. What's the level where it's fine for Apple to say "we want this much extra just for us"? For a lot of people the answer seems to be "zero!" — while this probably would not disincentivise Apple from making iOS given they also profit on the hardware, it would almost certainly disincentivise Google from bothering with any updates to Android.