Always said it would do considerably worse than the Wii but honestly did not see this coming. I don't think I have any specific number until after the thing had launched, if I had made a guess before it did, I would likely have guessed somewhere in the 40 million region or so.
I did recognize the Gamepad as a potentially big problem right away though, but underestimated how big that problem would be in conjunction with the overall design, pricing and costs and super slow 1st party production.