True, but by that logic, it would almost make sense for Apple to go to a 2-year upgrade cycle, since the 3GS to 4 upgrade is also definitely worthwhile for thos

True, but by that logic, it would almost make sense for Apple to go to a 2-year upgrade cycle, since the 3GS to 4 upgrade is also definitely worthwhile for those users. The main reasons they didn't already upgrade are not being off contract yet, and waiting for the iPhone 5 release.