I think you have a decent prediction, but I find some of your arguments a bit skinny.
So I'll do it another way, a bit more statistical (of course - it's me after all :P)
SMG sold 2549K in 2008.
By quarter:
Q1: 1179K
Q2: 663K
Q3: 421K
Q4: 786K
So as we can see, it is dropping pretty swiftly (compared to many other very high-profile Wii games).
It's likely that we see something ala
Q1: 325K
Q2: 275K
Q3: 225K
Q4: 450K
For next year. That's 1275K. Almost in your expected range.
I do, however, not see 2010 being as high as you claim. I see it rather being ala
Q1: 200K
Q2: 175K
Q3: 150K
Q4: 300K
Which is just 825K.
Then the sales will dip to ~ 500K for 2011.
Whicever quarter gets a price cut will probably get an increase by 25-33%, and the following by 10-20%.
Also, around 200K could be sold [2012 and out, more if the next Nintendo console releases later (but that's just a matter of 150K)
So somewhere around 3M is where it sits at for me. That's a bit lower than I expected when I wrote this...
So my overall prediction: 11-11.3M
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS







