I'm going with an expanded stages of grief theory. When people started buying the Wii like hotcakes, the doubters used either one or all of the following major coping strategies; the "fad" defense, "no ones gonna buy games" defense or the "casuals" (and the closely related "your not hardcore") defense.
This denial persisted long and hard, flying in the face of sales figures and logic lasted until the arrival of the dynamic duo, Smash Bros and Mario Kart. Smash Brothers was supposed to be too core for the casual Wii base and Kart was supposed to be selling only to the "Marioboys" who had all already purchased the Wii, obviously. A logical conclusion, considering the number of Wii's sold prior to the arrival of the dynamic duo was almost exactly equal to Gamecube numbers plus extras, the infamous soccer mummies and wii-mote wielding grannies. Scarcely less than two months later Smash Bros has hit nearly 5 million units in a race that I'm willing to bet isn't even half run and Kart's hit nearly 2 million in as many weeks with engine's still idling, and a territory still up each of their respective sleeves. The anger phase typically doesn't last that long so I'm just going to let that play out but watch out for my next article, "Wii-fit and the bargaining phase";)