I agree in most points here, but NO, they do not have to support PWA. If anything the locking between only Android and iOS is the issue... perhaps if there was a viable alternative it would be force them to support them.

I adopted WebOS, Windows Phone, and with no other options I am on Android. I do think iOS works in a way better than the fragmented Android. I also have an iPAD and I don't love it either. But much like you are stuck in each platform programming in their own environments, you that is the environment you decided to use. Windows also pushes updates, and it does break legacy applications without a care much like Apple. I am not defending either, because at this point I am disappointed at both and expected very little from it. If you are really committed to change then try Ubuntu (or any linux distribution you like) and the Pine Phone. Otherwise, you have to accept their platform choice.