You know... I do believe media sources that say that people in their teens and twenties are the ones that reject and don't play adventure games are DEAD wrong.
I think we may be the exception rather than the rule, though (22, btw). A forum dedicated to adventure games is going to be likely to attract those in the teen-twenty range who do enjoy adventure games, but I would assume that there are more who are into Halo, WoW, Half-Life and games that have high-quality graphics, lots of action and console versions.
Not that there's anything wrong with those games (I love Half-Life and its sequels), but when games that are more action-oriented are the trend, people will tend to follow it. I think this is especially true because people will tend to do what their peers do because it's "cool."