I think people should lay off the ridicule a bit. If you think he's wrong then just tell him why. We also don't need this to turn into another brain damage inducing thread full of ignorant stereotypes.
Now, regarding the OP, while it's true that the US market is the biggest, it's hardly the only one that Microsoft cares about. You're exaggerating to ludicrous degree. Also, I assure you that no one would take 10 million US sales over 15 million worldwide sales. Just look at how much money Microsoft has spent in Asia trying to push the Xbox brand. The money they've spent in Japan alone has to be significant by this point.
Honestly, the most successful businesses--which certainly includes Microsoft--understand that the potential for growth in the rest of the world is enormous when compared to the US. They want in on that and they want in on that badly. Just look at the film industry, which is seriously becoming focused on the global picture.
That growth has all the players in the entertainment field salivating.
