If only that were true. Unfortunately, the number of windows users on windows xp dwarfs those on vista or win 7. Maybe that will become more true in the future, but it's not a pressing force for change now.
I could quote you on that and change "windows xp" for "Fsim 2004" and "win 7" with "FSX"... of course majority of people still haven't upgraded. I still like XP, but we have to face it, moving forward you just need 7. XP chokes with more than 4 gb of ram and more and more it makes sense to have 4 or more. 64 bit support is a lot better in 7. Not to mention the new graphic cards and Direct X 11.
For me it was quite easy. My gaming rig which runs on an aged hardware I upgraded as much as I could, runs XP.
My laptop which came with Vista originally, ran XP for a bit (when I got extremely pissed at Vista's bullcrap) and now is running on 7 because the hardware in it just works better with this kernel. Any computer newer than 1 year should be on 7 already.
I could also mention both these computers are dual boot with Ubuntu, but thats another matter
