Yes my i7-930 was more than I needed when I bought it and will be for some time, but that doesn't mean I want to go buy a SB setup, then a Ivy Bridge, then a Rockwell, Haswell, etc. Do I have the money? Maybe, but there are plenty of much more worthwhile things I can do with my money (charity, help friends out, etc.).
For some it is a way to get their kicks to always stay on top, but for me it's just fun to be able to participate at a relatively high level if only for a short time every few generations.
Just my $0.02.