iOS is an option among several, not the only game in town. Nobody forces anybody to buy iOS, and if they don't they don't need to use the iOS App Store either, problem solved...
Nobody forces you to buy a Ford or a Chevy either but both of those manufacturers have to follow very strict rules about how they make and sell cars.
If our country decides to make a rule about how smart phones should be created, sold or operated and Apple doesn’t like it, they can go and do business somewhere else.