Here's the thing, even if you say that there is nothing worthwhile on the Wii since SMG, how do you explain the sales of Wii fit, Kart, Brawl, all of which surpassed Galaxy in sales.
Saying that core gamers are better than casual is defeated by the continued success of the Wii in hardware and software sales, clearly the casuals are the better market.
The argument that casuals will leave is silly, its been three years and it hasn't happened, and in fact Sony and MS are trying to chase that market as well with the wand and Natal, of course they don't have the software, but that is a different story.
Predictions:Sales of Wii Fit will surpass the combined sales of the Grand Theft Auto franchiseLifetime sales of Wii will surpass the combined sales of the entire Playstation family of consoles by 12/31/2015 Wii hardware sales will surpass the total hardware sales of the PS2 by 12/31/2010 Wii will have 50% marketshare or more by the end of 2008 (I was wrong!! It was a little over 48% only)Wii will surpass 45 Million in lifetime sales by the end of 2008 (I was wrong!! Nintendo Financials showed it fell slightly short of 45 million shipped by end of 2008)Wii will surpass 80 Million in lifetime sales by the end of 2009 (I was wrong!! Wii didn't even get to 70 Million)