I will admit to not enjoying the hobby as much as I did a few years ago (I think it's the players, to be honest). I honestly think I game now because I wouldn't know what else to do, as there really isn't another of my old hobbies I enjoy now. I game because I must.
I didn't start gaming until I was over 30, after I met my now-fiancee. But I've always loved "let's pretend", and have been a halfhearted author wannabe most of my life. Gaming really suits both of those interests. I get to pretend to be someone else for a few hours each week, and tell a story. And I get to do it with people I really like who have similar values and interests to my own. Gaming has introduced me to all of my friends and expanded my social circle.
Gaming is fun and social and gets me away from things that bug me for a while. Its a hobby that is as cheap as I want it (or as expensive) and creative