It's not about whether people can choose not to buy an iPhone, really at all. It's about once they do choose iPhone, is Apple unfairly using their control of the platform to influence whether they choose Apple's product vs a competitor for future things they buy.
Do you see what the problem is with the above statement? How far does the government go? Shouldn't all products (electronic or not) be "open" if Apple loses?
Let's say there is an emergency breaking fix that is needed to make NFC payments reliable. Instead of just pushing the fix asap for Apple Pay, Apple would need to comply with these regulations and have to make sure other companies who implemented an Apple Pay competitor also have time to do the fixes. Imagine spending Apple employee hours coordinating this without any compensation to Apple. You'd have to beg 3rd party implementations to update their payment setup asap. Otherwise, the government/media might accuse Apple of unfairly favoring their own.
The only thing stopping this is Apple saying no. It wouldnt take any extra work to allow this, they just need to say yes and then everyone in the world can talk together no matter what platform or app they are using.
Its not about creating a free and open platform, its just about saying yes to letting others play with your toys.
Let's do the exercise.
This should've happened long before Apple made that first trillion, not now so late after the fact.