I think there are quite a few Wii owners out there who's game library in 2012 will look something like this:
Wii Sports
Wii Play
Wii Fit
Wii Sports 2
Wii Play More
Wii Sports 3
Wii Fitter
This new market that Nintendo tapped, aren't the same people that bought Ninja Gaiden 2 for 60 bucks on their 360 then bought MGS4 a week later for their PS3. They're people that buy Beanie Babies and Tickle-Me-Elmo's. Unless it's on the news, they won't even know that a new Zelda game was released or that Resident Evil 6 is out.
Fortunately for Nintendo, a lot of "real" gamers bought Wii's too. And that's why good quality games like Mario Kart, Smash Bros, Galaxy etc. are selling well.