But frustratingly, the AT&T website appeared to allow you to replace your current (auto-pay) billing method with some other billing method, but I didn't see any way to remove all current billing methods, which makes just stopping paying nigh impossible. :-(
Freedom to pay is very fundamental for free speech, I think courts and legislatures made this very very clear multiple times.
There are whole countries where you don't need Apple as intermediary to cancel any subscription without notice. In these countries it is up to companies to sue you if they think you are in wrong, and "they made it hard to cancel subscription" is basically all defence consumer ever needs.
So they never win.
So they never sue.
My naive take - it's because we give corporations just as much freedom if not more than the average person.
Then you have to go court to decide which of you is right, much easier to sit on the phone for a couple hours.