To be honest, I'm beginning to feel like Nintendo's problems are more systematic and more deeply rooted in who they are. It shouldn't be *this* hard to sell even 20 million consoles and you shouldn't need a miracle gimmick to sell every single console you make.
I think the basic formula that Nintendo has of selling consoles is still rooted in the 1980s ... that the home console is for kids first, with little Johnny playing Mario as his dad and mom watch over his shoulder and laugh on.
But I think game consoles have simply evolved beyond that to be a home appliance. Like a cable box or a DVD/Blu-Ray player (no one wants a kids centric Blu-Ray player).
Sure Nintendo has their "hardcore" base of fans who are actually mostly adults, but they tend to only buy a Nintendo console for the main Nintendo IP they grew up with as kids. They buy a Playstation or XBox for any other type of gaming.
Selling a game console that somewhere between a toy and a electronic gizmo mostly on the back of Disney-styled mascot gaming characters is just a format that I don't think appeals to a lot of people anymore. Even kids ... you would figure that Nintendo should have a stone cold lock on that market, but kids want a Playstation or XBox too by the time they get to age 10-11, they want to play what their older brother/cousin is playing.
That's why, from an advertising standpoint, Nintendo nailed it with the Wii. Trying to be too edgy is terrible; it comes off as contrived, and it would make Nintendo look silly compared to Playstation or Xbox. Going with a kiddy image forces you into a very niche audience. What they did with the Wii was similar to what Apple does with their advertising: Make the product a "for anybody" device. This is Nintendo's best approach for their consoles, IMO.