For me, it's all about taste and types of games being played. I'm slowly leaving the big budget market and going more towards the art-house gaming circuit and casual games. Sure I still love Call of Duty, Left 4 Dead, Grand Theft Auto, etc; but now I enjoy games like Facade (look it up, it's free and brilliant), Braid, and Bioshock.
I also feel at this point that games are now at the level of movies, and by that I mean that everyone plays games and watches movies and noone really outgrows movies, just types of movies. Do you think that at 50 years old you'll still be watching movies on the level of Transformers 2 and The Proposal? My guess is "no".