Microsoft provided security patches for Windows XP for 14 years. The way Apple and Google retool their mobile OSes every couple years seems deliberately designed to create a technical justification for ending support. And Apple pioneered this business model with the original iPhone.

It will be interesting to see how Windows 10 shapes up. It seems like a really well-thought-out OS so software patches never have to be stopped. Of course if Microsoft chases Apple to ARM we could see a repeat of when Apple obsoleted all old Macs by ending support for PPC.