NB: This is exactly the model that Apple also uses, in not providing newer versions of Mac OS X for hardware they are no longer manufacturing.
Actually, Apple supports it's Mac hardware with new versions of OS X for several years after it stops making it, and then continues to release bug patches and security releases for old OS's for awhile longer. And since it has adopted the strategy of making their old designs their low-end phones, old phone hardware lives for many years!
On the other hand, handset vendors that productize via carriers can't worry much about customer satisfaction with old devices, because they have no way to get carriers to release new versions for old handsets. So the situations aren't really parallel.