I'm 33 and I worry about that happening to me eventually. Every time I think that might be the case for me I run into another game that I love though. It's mostly single player games that I like, but occasionally I'll get into a multiplayer game. I think I'm finally done with Mortal Kombat X after some 500 hours of playing it. Surprisingly, that's probably the first fighting game I really put in the time to get good at. Playing it online at a decently high level was great fun.
The problem with most single player games is that I burn through them so quickly. I really enjoy single player games with great atmosphere and well told stories. Games like Alien: Isolation, Bioshock, and Soma always hook me, but I finish them so quickly. Really good RPGs like The Witcher 3, Fallout, and The elder scrolls games offer more playtime, but once I finish them I rarely want to replay them.
Right now I'm trying to slog through Dark Souls again, but I don't think I'm going to make it. The trial and error gameplay is bad enough, but the fact that they put a few minutes worth of enemies between the nearest save point and every boss fight just makes it a boring and miserable experience most of the time. Trudging through the same stretch of level for the umpteenth time to face a boss you know you probably don't know how to beat yet kills my soul. I just don't get what people see in that game.
In any case, give gaming a rest for a while if you don't feel into it. It shouldn't feel like work. Eventually something you're excited about will come around and draw you back in naturally. No point in forcing it.