Upgrades aren't so up
I think the main issue is the slow pace of mobile processor upgrades. I bought a computer 2 and a half years ago with 2 gigs of ram and 2.0 Ghz dual core, with 2.3 the top end at that time.
Right now average is 2.3-2.5 and absolute max is 3.3. They seem to be trying to make up for it with piling in 3-4 gigs of ram and larger hard drives, but the computer I have is still a fairly reasonable computer compared to the current market. This means that most people aren't buying upgrades, or going used if they know what they are doing. Or spending 300-400 for a netbook instead of a normal upgrade because at a certain point a faster processor won't make your websites or word files open faster.
Maybe once quad+ cores come out for notebooks there will be a surge, but I know I'm not getting a new computer until mine is at least half the speed of the market