Immoral or not, what is being said is: If I were to buy software X and place it on a box I control, without access to the internet, I expect it -- and its bugs -- to work forever. Ruling out time issues (y2k or similar), I expect notepad.exe (for example) or grep to work forever. I can extract from it all the use I am able to.

> If you value a piece of software, then (...)

No. Just no. If I value X, I value X. Don't try to con me into doing something else. It is "I value X because something.", not "I value X because I want something else to happen in the future." (in this case, maintain and improve the app). I may want to donate, or buy future products from the same developer, just so I can support him. But if I just value X, no further action is implied.

> As far as I'm aware, Apple will not force you to subscribe to any apps.

True. In the same way nobody will force you to pay taxes. You are not forced to pay taxes. But you are punished if you don't. You are not forced to use this app model, but you are punished if you don't. (if the current model of buying apps completely migrates to a subscription based one).