I've worked with many excellent programmers over 40, some over 70. You might want to look for companies that are run by older folk, and maybe in more establishe

I've worked with many excellent programmers over 40, some over 70. You might want to look for companies that are run by older folk, and maybe in more established companies. Anecdotally, I haven't seen a lot of 40+ engineers in Silicon Valley, but here in San Diego I've never met a Qualcomm engineer under 40. Maybe geography has something to do with it.