I see both sides of this subject: Windows XP, which I first bought and installed back in 2001, is without a doubt "the past", and it really makes no sense from MS's point of view to keep marketing software enhancements for it...simply is not a wise decision either from a business aspect, nor from a development aspect. Continuing to retro-fit software can limit the ability to add features that best serve newer hardware.
At the same time, old as XP is, it is STILL the first non-DOS OS (aside of Win 2000) closely related to not only Vista, but Win 7 as well. In fact, my less-then-1-year-old netbook, came with Win XP SP3 installed! Although Vista worked just fine for me, a lot of folks never really accepted it, and XP remained their OS of choice, so XP dos not "feel" as old as it actually is.
Though I am sympathetic to Coco15's response, I can not fault MS for not retro-fitting this to XP. Besides which, IE7, IE8, FireFox, Chrome, all run just fine on XP, so it is not as if the lack of IE9 is going to be ruinous.