I think several people may be missing a critically important point here about Focus Groups. There's a lot of ink spilled in the last few pages of posts I've read through about how (1) people aren't truthful in those groups out of pressure, (2) companies aren't honest about the data provided, (3) it should be done "man on the street" style outside of a select sample, (4) there should be better questions to encourage more diverse opinion, and/or (5) the consumer isn't educated enough to answer well.
I don't think any of that is the issue.
What the study/research shows is that there's a disconnect between peoples' answers (and this goes to scale, it isn't idiocy or ignorance or fraud or anything untoward) and their actual behavior. Too many people, I feel, are trying to make this a difference between the stated preferences of a focus group in an interview and the stated preferences of real gamers in a real gamer world.
I think that's short-sighted.
The disconnect is between what consumers genuinely believe they want (including real gamers and casual ones and weak ones) and what they actually spend time, money, effort, and joy experiencing. The astonishing truth isn't that companies do focus groups wrong, it's that most consumers (even those who think they know better) really don't know what they want--not very well. And in a world (like games, I imagine) where part of the art is the new experience, it must be much harder to position the next product in front of a consumer base that says one thing (and believes it) and actually truly deeply only wants another (which they don't know how to express).
In actuality, and likelihood, both the Dude-Frat-bro CoD gamer (whom people seem to disdain here) and the Gamecore (Tru-gamer) Guy are both bad at this. It'd would be born out in their actual playtime what they truly like and don't.