I don't see the Japan thing as so worrying, the 3DS is close to reaching the Game Boy advance in sales in Japan, most of the people who would buy a handheld already have one, you can't expect them to buy a console twice.
The 3DS should pass Super Nintendo this year, you can't abandon a +50 millions userbase to which you can sell software so quickly, I expect them to support them 5 or 6 years even if hardware sales remain mediocre.







