These aren't SF startups (see above). I see plenty of 30's and quite a few 40's, but where are all the 50's and 60's? These days I don't think many are passing away at that age, right?
I'm working on a hardware project right now and the guy that's doing the board design is 57 and retired. I can only call him between tuesday and thursday and he has an aol.com email address, but he knows what he's doing... so who knows...