Mooh, I'm with you. I've been playing with an acoustic/electric band for the last seven or eight years (lead guitar, mandolin, vocals), and fortunately we play a wide range of material, our own and other people's. But we don't always see eye to eye about where we should put our emphasis, and a couple of the guys seem like they never really left the 1970's (I'm at the upper end of the age range at 42, but most of the others are close behind me). Often they reason that this music is what the people will come out to hear (we play the bars and the occasional function, nothing approaching the "big time"), and part of me suspects they're right. I can still play that stuff, but it sure isn't where my heart tells me to go. So I look for opportunities to do something original with the tired old material, and I live for the moments when we're playing more of our original, acoustic-oriented stuff. If we were completely devoted to 70's rock and roll (or 60's, or 80's, and don't even talk to me about the next decade or so), I'd be out of there in a heartbeat. I'm also developing an acoustic duo on the side, which is showing promise in its early stages.
Life's too short to keep playing stuff that doesn't do it for you. If that means you're growing old, I'd say you should welcome it with open arms.