ah, xp, we hardly knew thee...
it is gawd-awful expensive to re-develop existing software to run on a new platform.
vista/7 are so radically different than xp, that it is far far better to keep xp.
i helped a m.d. move his in-house developed software from a 2003 server to a 2008 r2 server.
and unless you've ever done that, you cannot imagine the horrors that that involves.
(yes, he has a programing team.)
so, yes, xp it is for a long time to come.