Another reason, maybe not the main reason, is people buying an iPhone 4 to use as an iPod Touch. 3 months ago, I bought a 4 month old 32GB iPhone 4 w/bad ESN (in mint condition) for $210 for that very reason.
When Apple didn't update the iPod Touch, some who had been waiting for a new iPod Touch decided not to wait another year and do the same thing (buy an iPhone 4).
I've been looking to buy some more iPhone 4's for friends who really liked the idea, so I've been tracking the prices. When the iPhone 4S was announced (and no new iPod Touch), prices for iPhone 4's on ebay shot through the roof.
I'm sure there are other reasons as well, but I think that this may be one of them.
When Apple didn't update the iPod Touch, some who had been waiting for a new iPod Touch decided not to wait another year and do the same thing (buy an iPhone 4).
I've been looking to buy some more iPhone 4's for friends who really liked the idea, so I've been tracking the prices. When the iPhone 4S was announced (and no new iPod Touch), prices for iPhone 4's on ebay shot through the roof.
I'm sure there are other reasons as well, but I think that this may be one of them.