Pachter knows they won't plummet - but I agree a small drop is likely. Computer & Videogames is quite possibly one of the most misleading sites on the internet for this type of information (see headline vs. comments).
X360 Shipments:
January to June 2009 : 2.9 million (1.7m shipped in Jan-Mar, 1.2m shipped in Apr-June)
January to June 2010: 3.0 million (1.5m shipped in Jan-Mar, 1.5m shipped in Apr-June)
Personally, without a price cut, I would have expected X360 shipments to be about 4.2m (down from 5.2m in Oct-Dec 2009) in Oct-Dec 2010 if Kinect didn't exist. But since they'll advertise that and create some interest for it, shipments will probably be 4.8m-5.2m.
Its a bit of shame they don't seem to be cutting price, because it probably means the maximum value for X360 hardware shipments in a year will be 11.2m during April 2008 to March 2009. They're only off 10% from that peak, a price cut could have gotten them to 12m-13m in a year.
People are difficult to govern because they have too much knowledge.
When there are more laws, there are more criminals.
- Lao Tzu








