Which, in the days before the Apple App Store, when one had to contact Verizon or AT&T to get your app available to cell phones, was the other way around. They would take 70%, and give you 30%.
But a few years pass, and now it's the Apple Tax? Some people could promote and sell it themselves for less. A lot less? Maybe, maybe not. But most of us could never ever do it for the 30%. Why does everyone think they're the smartest one in the room these days? Odds are, you're really not. Sorry. You're just not.
They are using their monopolistic stance to kill others. But then it's their platform and they can do as they please. They gotta make the $$$ to keep shareholders happy with ever expanding profits.
Welcome to America.
The counter-argument is of course the PC era, where you could sell stuff and give 0% to the manufacturer and OS vendor.