I don't see the logic about casual gamers being people who have a life outside videogames. Not all gamers are school children. Also, one can be socially devoid and spend his time playing virtua tennis.

It is IMO on what games you spend your gaming hours. Plus, you can be hardcore at something but not a hardcore gamer. Plus, hardcore gamers do play casual games, but casual gamers rarely if ever pick up Megaman and complete it.