I can see why Sony would prioritize the US. We are the biggest and most fickle market. Europe seems loyal to Sony, while in Japan the home console market is becoming less relevant every generation. In the US we pick a new winner almost every generation, or at least we go from total domination to a more even split like in Generation 4. There was that one time we picked Playstation twice in a row just to show how truly unpredictable we are.
In the the US XBox, Playstation and Nintendo are all solid brands, and the companies seem to always compete here the hardest. The playing field here is fairly level, so this is where companies seem to focus their competitive efforts.