I don't know where people get the idea Nintendo is doing so poorly. As far as I'm concerned Nintendo consoles and XBOX/Playstation shouldn't even be in the same category. Nintendo has and continues to offer innovations in types of games and the way they are played.
PS and XBOX continue to pump out the same types of games over and over. Namely first person shooters and sports games that change little from year to year. All those consoles can brag about is increased graphics capability and media capabilities such as playing DVD's and internet access. They're no longer in the gaming category IMO. They're low priced PC's that overheat easily and require expensive upgrades to their memories to play most games.
Nintendo is in the business of creating new ways to experience gaming. From the first RPG's to games like Elektroplankton...Nintendo always brings new experiences to the table. The American mainstream may not eat it all up but that certainly does not make them a wounded dog. Hell the DS is single handedly responsible for masking the HUGE decline in sales of all other consoles in 2005 alone!!
*End rant from DisJosh the Nintendo geek* lol