As for the 3DS only having good sales in Japan, here's a break down of it's sales by region as of Sepetember 2012:
Date------------Japan---America------Other----Total
2011-03-31------1.06------1.32-------1.23-----3.61
2011-06-30------1.27------1.43-------1.63-----4.32
2011-09-30------2.13------2.13-------2.42-----6.68
2011-12-31------4.66------5.47-------4.91-----15.03
2012-03-31------5.85------5.99-------5.30-----17.13
2012-06-30------6.76------6.41-------5.82-----19.00
2012-09-30------7.94------7.38-------6.88-----22.19
As you can see, it's actually selling evenly between America and Japan. The thing isn't selling bad at all. Yes there was a dip in the US in the summer of 2012, but I won't be surprised if it rebounded for the holidays. Not to mention the recent announcement of Pokemon X and Y will probably make the sales start to go up. By October of 2013 expect the 3DS to be printing money for Nintendo. Sure mobile stuff may be great for the casuals, but you won't be able to get the new Pokemon game on your iPhone, and that will make a difference as always.