The majority of individuals that monitor/read/post in this forum are in to demanding games. That is not a majority of PC users. I know of no one at work (EEs and PhDs) that are into games including myself. At work, they are stuck with XP Pro until NASA Langley upgrades. SC(&% XP, I still maintain 3 Lab Computers (P-90s) running win 3.11. These 3 computer control a Satellite instrument and to upgrade them is probably in the => $100K (This includes software development).
Myself I have migrated to mainly Win 7 (Dual boot to vista on this computer). I've pulled my XP disk and put in closet.
My wife represent a good # of users - internet, email, some programs (Word. bowling secretary, embroidery) and "low end games" that will run on a 5 yr old computers just fine. Her views on changing/upgrading her XP coincides with my guns - YOU will have to pry them from my cold, dead. Hands. - or in her case when she has to get a new computer (One of my newer hand-me-downs) AND then she will probably force me to re-install XP.