This maybe sounds smart until you take a few seconds and notice the crazy amount of work these companies put into doing the exact opposite of your premise: preventing you from installing alternative operating systems and preventing you from using alternative marketplaces. When Apple claims they have to do extra work to make their devices support alternatives that is them lying to you and you are apparently eating it up :/.
It's far more work to create a free for all platform (what US & EU governments want) than a single product that has no external specifications.
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.
Again, this sounds smart until you think about it. Apples apps such iMessage use a protocol which Apple developed. Its not even secret how it works, people have reversed engineered it multiple times and are ready to use it in other apps so people can chat to iPhone users with no issue.
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.
When you open something up, you have to do a lot more work than just using it internally. Maybe 10x more. Try opening up your API up for external use instead of 100% internal.
