This is a really bad take.
People do not merely pay for the rearrangement of atoms into what ends up being their phone.
The software is critical and deserves all the money earned to make it happen. Apple still stands up all those servers, engineers, and operations for apps priced at $0 -- at min-cost to the developer (before you start: no, $99/year covers zilch; $99/year is a mode of spam prevention dev account creation).
It is unreasonable, nefarious, and even grand theft for anybody to make money on the phones and refuse to pay for the services that made it possible: the software engineering into Swift, Xcode, CoreOS, Darwin, FoundationDB, Data Centers, the engineers on on-call rotations, and who knows whatever else. All those things don't come for free. App developers who make money off the ecosystem should be held account to pay up.