I haven't heard any reports about PS3 and 360 shortages throughout the year, but many for the Wii.
I would think that anticipation for Galaxy would count towards a slight increase, maybe not a huge increase, but a factor towards it.
People start paying more attention to advertising this time of year. People are discussing presents for Christmas, and advertising would play a big role in this.
Metroid Prime 3 was just an idea.
---
You also have to remember that the declines for the PS3 and 360 were expected. At the prices they are, they can't expect to maintain Wii-threatening levels of sales. The Halo effect is wearing off, as with the PS3 price cut. I believe that the H3 sales, and the PS3 cut sales were higher than what the Christmas sales are going to be, so a decrease would be expected.







