Interesting that you mention the kindle - wouldn't it also be nice to be able to buy Apple Books on your Kindle hardware? You also can't do that. You can root some Kindles and install other software, but is more or less like jailbreaking an iPhone.

The issue I have with people going after Apple is that _everyone_ does this more or less.

Broadly, I have the fewest complaints about the restrictions in Apple's ecosystem as a user.