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In retrospect, it shouldn't be a surprise that Apple released a half-step iPhone this week, instead of a revolutionary and redesigned iPhone 5. Think about it--the real reason for the iPhone 4S is the same as for the iPhone 3GS: carrier contracts are two years long.
The 4S isn't meant to be an upgrade for iPhone 4 users--it's a lure to get new iPhone users in the door, and you iPhone 4 folks will get your iPhone 5 upgrade just in time for a new contract. And if you decide you can't wait and spend big bucks to break your contract or buy the iPhone 4S at full price...well, that was your choice, wasn't it?
Look back at Apple's iPhone release history and you'll see that the iPhone 4S is just the next step in the product evolution, which went from 3G to 3GS to 4, and now to 4S. It actually makes perfect sense, once the lust for new technology and new Apple hardware starts to subside. If anything, Apple is playing a very clever shell game with carrier contracts that allows it to grab new buyers every year instead of every two years.
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