[copsarebastards]

There's a flipside to this: middle-aged-to-old people aren't choosing to participate in the silicon valley startup culture. As superuser2 noted, a 22-year-old can subsist on ramen while living in a car, while a 45-year-old can't ask his wife and children to do that. But it runs deeper than that: just because a 22-year-old can subsist on ramen while living in a car doesn't mean it's a rational choice.

Most startups these days are producing glorified ad servers that don't actually solve any problems or provide any value. The tech bubble is such that anyone with a young face, a Macbook Pro, and a dumb idea can get funded, but that won't last. As such, working 60 hour weeks for stock that will be worthless in a decade is a bad idea for anyone, regardless of age. Software devs in their 40s have the self-respect and experience that they won't take that kind of deal.

There are some startups which have reasonable business models, but I suspect that time will show that part of those reasonable business models is recognizing the value of experience. In the long run 45-year-old programmer with 25 years of experience working 40 hours a week is easily worth two 22-year-old programmers with 2 years of experience working 60 hours a week. There are certainly young prodigies and ideas which hit the zeitgeist so well that the execution of the idea barely matters, but these are outliers, not the norm.