A great example of the subtle ways the industry can be manipulated are in the selection process for journalists.
Consider, for example, two prospective gaming journalists, one of whom has a preference for mechanical complexity -- perhaps highly elaborate strategy games a la tabletop gaming -- and another who likes to blow stuff up a la most AAA games this generation.
It is likely that the guy who naturally prefers tabletop gaming is going to give higher scores to games like Hearts of Iron III, while the guy who loves the big titles from the current big Western publishers is likely to give better scores to games like Call of Duty or Gears of War or Killzone (and perhaps he does not review HoI at all).
I believe that second prospective journalist who is really in to AAA "blockbuster" gaming is much more likely to get and maintain a job in the gaming journalism industry. In other words, I think in some cases manipulation of journalists is unnecessary -- the journalists are essentially pre-selected because of their predilection for what the AAA Publishers are already doing. It's a lot easier to get an endless stream of 8.0s and 9.5s from people who have already bought in to the system before they're even given the job.
I think that's true, and also find it frustrating that reviews for specific games are so often given to the person on staff most likely to like that game. Halo reviews are always done by the big FPS fan, Starcraft reviews are always the RTS guy, etc. Movie reviewers review movies of all types, not just their very favorite genre(s).
A lot of the potential audience for a game isn't necessarily genre/franchise superfans, yet that's usually entirely who reviews them.