That's a fairly odd comment from a game developer, given that any product in development now is probably going to have minimum requirements whose hardware exceeds what will be supported by XP anyway.

As for Windows Embedded, it's a whole different kettle of fish. It has a long support lifecycle because appliances are developed, shipped and then sat out in the wild for a long time before they're replaced. As such they aren't generally subject to the same kind of continous maintenance and app upgrades that a normal application would be.