Nintendo isn't doing so hot right now. Sorry it's the truth and it happens. Businesses ebb and flow based on the economy and demands in their market. Nintendo's problem is now and has always been a willful ignorance of their market. They've sold Mario games since 1988 and never changed. Mario games are always full price and you can't try them before you buy. That doesn't really matter; you know if you want another Mario game before it is released. I thought when the Wii came out Nintendo may have changed its stripes that it was finally going to react to how people played games. Instead they expanded into a market that quickly abandoned them. The difference is this when chasing the "core-gamer" you have a number of solid known expectations (graphics, competition, longger gaming experiences) the expanded market or "casual-gamer" has very different priorities. (namely abstract concepts named 'fun' and 'value') This is why the 3DS is having a rough go of it.  
The 3DS cannot survive in the age of Angry Birds. Gaming can but the 3DS cannot. Why? How much would you pay for a system where all the games are free? $100, $200, $500? Forget data plans for a second and realize that you can buy an Android tablet that will run Angry Birds and other cellphone games well for less than $200. A one time fee (not counting wifi access) and you have a library of quick arcade-y titles literally at your fingertips. In this world Nintendo's (admittedly cool) $169 system that has games for $40 has a hard road ahead of it. 
Sony is also raining on Nintendo's parade with announcement of the PSVita. When the price for the Vita was announced it was the same as the 3DS. (I called that there would be a 3DS price cut 5 mins later btw) This hinges on the question of value. At the same price the PSVita offers a better value proposition. Sony is still trying to sell the market on a "home console experience on the go" philosophy. For $250 you get an HD(ish) home console that you can fit in a (big) pocket. The 3DS does not offer that feature set to offer. The 3DS graphics are better than the DS but it isn't as good as some of the PSP games I've seen. The PSVita's graphics are more on the level of the PS3's and Xbox's surpassing Nintendo's home console (and abandoned child) the Wii. Graphics only matter to the 'core-gamer' someone Nintendo isn't selling 3DS's to. That core-gamer has already left Angry Birds in the dust though. So Nintendo is losing a battle on two fronts; they can't sell a system to people who don't want to pay more than $5 per title and they can't sell a system to people who want a core gaming experience. 
 The good news is Nintendo can still sell systems who want to play Mario. The bad news is those sales won't keep them in business forever.