Microsoft wanted to kill XP (or rather stop any support for it) since Vista came out. Unfortunately XP was as successful as IE6 and similarly doesn't want to go away. Windows 98 was similarly successful, but times have changed and security risks that didn't exist when 98 was roaming the world are now reality. If you think that companies are lying a'la Nazis about security think this, MS was thinking about giving security updates only to non-pirated versions of their software, but then they realized that the rest would be security risk for everybody, so they bit the bullet and gave patches to everyone (not that they don't think of new creative ways to milk consumers :)).
@bking01: Can you tell me of ONE SIGNIFICANT advantage using Office 2007 in MS Word, worth the HASSLE of dealing with that God-Awful Ribbon and the impossibility to customize menus and toolbars the way you can in previous versions?