Well I never said anything about it being now lol
But XP 64 bit was out for years (An uprated version of Server 2003 64bit), I was running 4 gig of ram on that quite nicely, mostly untouched by the public due to lack of manufacturer driver support, so obviously it will mostly be server side to begin with.
Anyway 32bit will be an option for a while due to MS covering older spec hardware.
The problem lies in the manufacturing companies holding off writing drivers for their hardware, they would rather it go obsolete and make you buy newer peripherals ( printers, scanners etc etc ) than have to put an updated driver out.