I have more trouble with Firefox than modern versions of IE.
I also have a Pentium III that's running Windows 7 and IE9 now (and will be able to upgrade to IE10), and if that can upgrade to IE9, it's utterly and completely disingenuous to claim that the "smallest fraction" of Windows users can upgrade to it. Instead of being rational, you come off as a sneering cheerleader and, y'know, that can entirely be your bag if you want to pick it up and run with it, but it'd help if you at least used your mouth for talking instead of parts down below.
The point is having a Pentium III Win 7 machine covers using a Pentium 4, Athlon XP, and all those other old computers to install IE9 - covering the biggest fraction of users through backward compatability.
You can run Windows 7 on pretty much anything that will run Windows XP. "It costs money to upgrade" may prevent you from doing so, but at this point, after a decade, it's not Microsoft's problem if you're not willing to spend the money. They're not obligated, nor should they be obligated, to avoid using their new stuff (Direct2D, for example) in order to continue to target XP users.
I also have a Pentium III that's running Windows 7 and IE9 now (and will be able to upgrade to IE10), and if that can upgrade to IE9, it's utterly and completely disingenuous to claim that the "smallest fraction" of Windows users can upgrade to it. Instead of being rational, you come off as a sneering cheerleader and, y'know, that can entirely be your bag if you want to pick it up and run with it, but it'd help if you at least used your mouth for talking instead of parts down below.