You have to have a licensed copy of the OS you install in VirtualPC, so that's probably not going to work for a lot of people. Second, peripheral support within virtualPC is practically null, you can't run any 3D applications because the virtual Image can't see your graphics card.
How many applications don't run under Vista? I have XP Pro x64 (based on Windows Server 2003), and I haven't found too many programs that don't run on it (there were some Explorer compatability issues, but most prorams still ran). Also, why would this program be too late? Did Microsoft include XP/2000 application support under Windows 7? I would think that if Vista didn't support these apps, neither will Windows 7. Since 7 is based on Vista, I have to think this app is just as relevant (if not more so) now than before. If Microsoft doesn't want to blow it with 7, they needed to release this program when they did, to show they can support those old apps.