You just described why I don't look at iOS as a serious platform for anything I want to last.
Everything I do on iOS is "look, do and send and go".
My productivity ends up stored on my Mac, my messages and mails and not only on my iPhone or iPad, my games - stopped buying them for iOS, for mobiles games the few I want I keep Android and apks around.
And hmm, well I do expect from an OS that I deem worthy of becoming a main OS to be installable and downgradable at my discretion and to yes - support frameworks and code compatibility for a long long time.
It can be done, Microsoft and others have been showing that for a long time now and that's why I don't feel too guilty about asking for that.
Until then I still USE iOS, but very differently and that is okay I guess, but not compatible with Apple's goal of making iPad a PC replacement for example. (personal opinion, ymmv, don't expect anyone to follow me, just felt like answering your comment)
Glassed Silver:mac
PS: no need to hold back at all, you can support old AND new code. It works, Apple just has a long history of forgetting quickly in favor of change, albeit in code compatibility I don't think this is a good approach - again - for my taste. Never felt a need to change my thinking here, because everyone comes to their own conclusions.