I'd say we could have seen it comming.
The game sold almost 2.5M in 7 weeks, that's a lot. Nintendo do not want to overmake, and as BBs can be made cheaper in the future, they should try to keep it even.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS