Look harder, us older guys are out here, and there are a lot of us that just want to play. Just find a bunch of guys that you click with and go with it...
Most of the band scene here is guys in their 40s + anyway... The twenty somethings, at least here, for the most part are more interested in electronica and DJing anyway...
If you have physical issues, deal with them, if you have psych issues, deal with them, if either of those keep you off stage, take a break.
Change your orientation on what you want to do musically. For instance, I never would have thought or wanted to play in a country / blues cover band, but here I am at 48 chugging along on the low end just fine!