Nice idea, but it can be difficult to implement in practice. E.g. if you need to re-install the OS, stiff crap, you'll have to put on the latest one. Also, many apps in the store don't work on older versions of iOS.
Another example is Facetime. For me, Apple has broken Facetime - short of updating to iOS 7 - as the current iOS 5 version no longer works. If I could get iOS 6, that'd be fine. But of course I can't.
Don't get me wrong: I absolutely agree with you about not updating to new (slower) versions of the OS, but your claim that things will work "for many years" is perhaps questionable...
Cheers, A.
Ah yes, that is true. I guess I should clarify, many core functions (FaceTime being an exception) will continue to function. I guess it just hasn't bothered me much since I only use a few apps but yea it does get really irritating not being able to reinstall or wipe if necessary.
I'm still so utterly enamored that I get the same battery life on my jailbroken 5 that I did when it was brand new accounting for near-perfect scaling of degrading battery longevity.