Nick Bradbury nails it in Old Farts Know How to Code:
"Old farts" are often excluded from that (Ed: startup) culture, not because we're lousy coders but because we won't put up with that shit. We have lives, we have families, we have other things that are important to us. We're not about to sleep at our desks and trade watching our kids grow up for the promise of striking it rich. Especially when the people who really strike it rich aren't the ones writing code.
I guess at 44, I’m treated as an “old fart” programmer now too. But he’s right, I am in my professional prime, I write better code now than I ever did, I know what works and what doesn’t, and still manage to have a life, family and friends.