Performance is no longer the driving force compelling a lot of people to upgrade their machines. Smaller form-factors, longer battery life, wireless connectivity, portability, and weight are the primary motivators for a lot of people. Just look at the Macbook Air, when it came out I knew dozens of people who dumped their 17inch Macbook Pros for it because it was good enough for their needs from a performance perspective and kicked the shit out of the MBP in every other measure.