There isn't really the same incentive to upgrade your PC these nowadays as back in the 90's. Very little software available today tends to stress even the mid range systems. There's a big trend towards laptops and more recently netbooks so I'd say 'gaming' PC's are going to go the way of the dodo.
I've fallen somewhat out of love with PC gaming recently due to the DRM. And I'm playing PC games for 15 years so it's not like I'm unaccustomed to these things. Bioshock was an absolute nightmare to get running. I had to reinstall it 3 times. GTA4 was also an absolute pain in the arse. You had to register for two different online accounts, it takes 45mins to install and I needed new drivers which weren't made available for my card till a month after the games release.