I think it is much simpler than that ...
1) For the most part "Analysts" of industrys like the videogame industry really started to exist in any numbers in the mid 1990s, mainly because of the increased size of the industry. This means that most anaysts started working in the wake of the rise of the Playstation and any bias towards Sony would have never been tested before.
2) Analysts are not gamers, they're people with business degrees who work for large investment firms. Their projections are heavily based on brand recognition and other abstract concepts which have very little real impact on the market; on top of this they don't have an understanding of why a consumer would choose the Wii over the PS3/XBox 360.
3) Analysts are amazingly well paid, and have very little connection to the realities that the typical consumer face. They will often assume that while people are spending $5/gal or $1.75/litre gasoline, their food expenses have gone up 25%, and they have lost access to credit, their #1 priority is a $1500 plasma HDTV.
