I will oblige your flame bait, might it have to do with the complete lack of applications to run on Linux causing alot of idle time on those CPU's.
:)
I'll respond by indicating that I'm currently primarily a Windoze user but am running ~50x the normal processor hours/day to support this team effort. The vast majority of my cpu cycles are NOT "spare".
I'd guess that the average Linux user has faster hardware than the average Windoze user. I shouldn't really speculate about the Apple users beyond noting that they may have [had] excess money.