Then in comparison to the single highest selling ds game, which has sold 20million copies at i don't know what price (lets say $10 average
10 dollar average? Nintendogs cost 20 pounds on Amazon UK (which tends to be far cheaper than the average in Europe).
That's a 30 dollar average in Europe. Amazon in US has it at 30 dollars, but I guess 25 would be on the safe side.
So a 25 dollar average is pretty much the minimum (it is being pretty pessimistic, I would guess it is ala 30-35 dollars)
Other than that, I agree with you, and this only makes your point even stronger.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS