I assume it's tailored in that way to get the most clicks.
All the figures in that article come from Pachter's regular data estimations.
He conducts a small survey of channel checks from a variety of USA retailers and formulates predictions based on that + NPD precedent.
Pachter's predictions:
PS4 - 175K
XBO - 150K
3DS - 90K
WIU - 65K
360 - 45K
PS3 - 30K
PSV - 15K
WII - 12.5K
DS - 0.5K
What the author of this article fails to understand is that Pachter is nowhere near definitive on the matter.
GAFfers have also made this mistake in the past when they would create threads dedicated to reporting Pachter's predictions.
And yes, you're correct. PS4 sold 863K in December 2013 while XBO sold 908K.