I think it's a normal function of "growing up" - certain hobbies or activities are more fulfilling than others, and as we age, priorities change, demands on our time change, and as a result, the less fulfilling activities lose their appeal. Ten years ago, I was into multiple hobbies - video gaming, astronomy, model rocketry, model railroading, to name a few. I tried to keep active in all of them, but with kids, a job, and just generally less "energy", it was too much. I no longer own any rockets, or participate in the hobby in any way. My telescopes sit forgotten in boxes in the basement closet. Piles of video games sit unplayed, except an occasional round of Civilization (rare). The railroading is where I spend my free time now, at home, at club events, shows, etc.. It provides everything I need, relaxation, a creative outlet, interaction with others, and it's fun.