For the most part, Microsoft focused the original Xbox on the American market. And Japan ignored it. Both because the PS2 was, without question, the King in Japan. But also because next to nothing on the original Xbox interested them. The only real thing that pushed consoles (or games) on the original XBOX was games from Team Ninja (Dead or Alive, Ninja Gaiden, etc). And even then, it was MUCH less than they probably would have sold if they made the games on the PS2.
When it comes to the 360...Japan just isn't interested. In America, you can sell games based on heavy marketing and the promise of pretty graphics. But in Japan, its all about name brand recognition and content. And the games on the 360 don't have any of the brands Japan wants, aside from one Tales game, one Idolmaster game and a bunch of new 'Japanese developed' IPs. Its hard to coax an entire market to buy your product when you already basically ignored them for a generation and then try to placate them with games developed more with the emphasis of making fancy graphics, but not delivering anything new content wise or the major IPs they are looking for.
Six upcoming games you should look into:
