Go into an Apple store to buy the iPhone 4S, only to come out with either the 4 or 3G.
We’re driven to the store by the excitement of newness but end of taking the better deal. It’s the ones obsessed with technology that take the bait.
The main difference between 4S and previous versions is a better camera and Siri. For many (like 4 million), those features are enough of a reason to upgrade.
The people that upgrade tend to happier, at least for the moment until something new is announced.