See, this is why the definition of hardcore gamer has been skewed more than shrimp.
First, hardcore gamer meant someone who could master any game, discover its secrets and become a legend doing it. For example, the guys from the movie "The King of Kong" are hardcore gamers because they spent time AND MONEY trying to master various arcade games, developing strategies and trying to become legends doing it.
Second, hardcore gamer meant someone who loved gaming a lot. IE, bought all the consoles, bought more than 10 games for each console, dedicated his time and money to gaming and his main topic of discussion is gaming.
Now, a hardcore gamer means someone that plays a lot of mature titles, usually ones involving a lot of shooting and death, plays online heavily and thinks any other console is worthless unless it has "mature" titles.
So how can we determine the average age of the hardcore gamer when the very definition can't be applied as well as it should?
