I just realised that I think Wii Play is likely to outsell SMB.
Anyway, I'm not sure Wii Fit + will kill Wii Fit.
You know Brain Training? It was out for a year and a half, then Brain Training 2 came out. It has kept selling at roughly the exact same pace as it did before it launched.
Is it so unreasonable to think that Wii Fit + is an attempt to pull a Brain Training 2?
Now, Wii Fit won't do what BT2 did. Believing that Wii Fit will sell half of what it does now after it launches, though, may be reasonable.
But that won't be easy to calculate, as Wii Fit is skydiving in its weekly sales. Will that keep happening? If Wii Fit drops to 70 dollars, will that make it hit a sweet-spot, spiking its sales back?
I think Wii Fit could keep up a good ~ 60-70K pr week after the holidays. With a price drop, somewhat more. As Wii Fit should be at ~ 26M by the end of the year, that would lead to me believing that Wii Fit will sell 30M by the end of 2010. Or well, somewhere around that.