Kreidel, I feel in a similar way.
For me, it's a combinatin of both factors you mentioned. First, games are indeed not what they used to be for the most part. Sure, there are some exceptional titles such as Dragonage, STALKER or Metro 2033, but even these games are somewhat lacking in "soul" although they come pretty damn close to what I enjoyed when I was in my teens.
The second factor is probably not so much the age itself but the responsibilities that come with age. I started realizing lately, that I spent my life playing video games, instead of looking for a nice girl, trying to get a good job/education, working out or trying to improve myself in some way. I turned into an antisocial freak, incapable of feeling comfortable in large crowds, parties or while talking to girls. Altough I am not fat by a long shot, I grew a belly, and I am in a pretty bad physical shape. I used to play basketball, and I used to be pretty damn good (for a white boy), but now, I can barely last 5 minutes on a court!!! I used to rollerblade like a manic, all day, even able to do some tricks.... Now I cant even stand on these things.
I realized the error in my ways, and despite great fear and anxiety, I came back to college, which I really regretted at 1st, but then I somehow got pulled in. I started working out, and I am now in much better shape. I even dated a few girls, although there is mostly no luck in that deppt. The most important thing is that I simply got no time for games! I work from 9am to 5:30pm, and when I get off work, I go straight to the gym. By the time I get home, it's 9pm and I am tired like a dog. The only thing I can do is either do some homework for college since it's piling up like crazy, or drop to bed and fall to sleep within minutes. Sometimes I WANT to sit down and play a game for a change, but most of the time I simply CANT! Only two games I played lately are Dawn of War 2, and RUSE beta. Dow2 seems like it's garbage at 1st, but after a while it gets really good. (Not as good as the original off course) RUSE, is so damn good it actually "almost" pulled me in as much as those older games I used to enjoy. I am looking forward to the full game coming out.