There are two types of people. Those that buy Model Number iPhones, and those that buy S series iPhones. (tweet this: http://j.mp/nY0qE8)
This being Apple, it's easy to attribute to stratagem what's probably just a coincidence – but it's quite convenient how this has worked out in recent years. A new iPhone model gets launched, and the early adopters switch to it, come hell or high water (read: angry wife or contract breakage fees).
The late majority, however, choose to wait and see. Next year, the S model gets launched, and it's time for them to move.
Conveniently, typical cellphone contracts last 2 years – a perfect cycle for both the tame early adopters, as well as the last majority.
It couldn't have been designed better if it had been Designed by Apple in California. Oh wait…
Thanks to Kent Brewster for making this idle thought post-worthy.