I know its amazing an OS that is 10 years old is still being widely used...that’s impressive!
"10"?? Try 13 -- XP came out in 2001.
XP remains viable because it is very effective. It was the first widely used NT (non-DOS) Windows, and after Microsoft finally got the security tightened down enough that it was moderately safe to use, and people got used to it, it kicked serious ass in every market segment including embedded systems.
Vista coming out both late and lame made it inevitable that XP would live forever.
I fully expect that XP will remain a viable and significant presence in the Windows landscape for another 3-4 years at least, and will still be the OS in millions of embedded systems (kiosks, ATMs, displays, etc.) for another few years beyond that, until all the machines die of hardware rot.
A VERY impressive achievement.
That said, people really should be on Win7 now. The lack of security updates is a serious security issue for XP diehards.