For a little while perhaps, but MANY of those XP machines are going to become effectively obsolete in a few more years. Clearly, when upgrading machines, you'll want to select a OS that is fully supported. IOW, while the "death" of XP may be a bit premature today, it still is eventually unavoidable, just like 3.1.
FTR, I have 7 installed on all of our home machines, our family business machines, as well as the 28 machines at a not-for-profit I help to run. I don't have a single complaint. The transition was effortless.
That's typically how businesses upgrade, when they buy new computers. I've got several older P4s and Windows 7 works good enough on those with a little more RAM. Also no problems getting older printer, network, and Intel chipset drivers to install.
So many can upgrade that way if their boxes are still good enough to use. In that case they could hold off until XP is no longer supported or wait until Windows 8 is released. Or even worse for Microsoft take a serious look at Linux as it continues to mature.