That was my point though, that it's impossible to target a market correctly because you can't categorically say which market plays which. I'm sure their are numbers to support a majority of any one market but the culmination of all the others you'd be missing would be wasteful to ignore. I got that phrase from the developers of Starcraft by the way which I feel took it to it's most amazing level of tangibility. The game is played by virtually everyone because it's fast and destructive and the units are easy to understand; However, the game is so perfectly balanced and deeply strategic that it single handedly spawned e-sports and competitions such as the WCG. It's an actual pro sport in South Korea. I agree that this is something that is very, very difficult to achieve but if it's possible and the game you're currently designing isn't a movie remake or some variant aimed at not doing much then such a theory should be employed. Am I aiming too high?
As for age ranges, fans, and other specific markets. I still have a hard time believing any one market plays only one style of game. I'm no marketing genius or by any means an actual game designer so I don't mean this to sound as though i'm saying "I'm right, you're wrong" I just ask a lot of questions and theorize a lot in general
I do agree however that targeting a specific market does help define the goals and other variables of a video game, I guess my problem is that it sounds like marketers are overthinking these target crowds and trying to break them into smaller clusters than I feel they really are. As an avid gamer and aspiring designer my interests lie in all types of games, consoles, design, and effort.