I can think of quite a few reasons. For instance if you have a program
that wants direct access to the hardware XP won't let it.
That "little" limitation broke my GSR monitor, my high sensitivity
thermometer, my weather station .... blah blah, the list goes on. (Even
my doom game)!
Besides, if XP is so excellent then why is this newsgroup full of
problems here ? Why do updates spew out of microsoft ?
Just my 2c worth.