Anyway, I don't think anyone is saying that it's 100% impossible to find tech work if you're 45. I'm sure there is work, and I'm also sure it's the case that Bay area tech is different from elsewhere. But one of those differences is what gets produced- nobody is designing the iPhone outside of SF Bay, to put it bluntly. And it's important that work at that level is not age-discriminatory.
I'm 35, just started at a Bay area company, one that makes really nice products and has some of the best designers anywhere. And I can already see it coming, so many of the people I work with are 25-27. The people who founded this company are a good bit younger than me. The grey hairs are people like the general counsel. Sure, nobody asked my age, and I look younger than I am anyway. But still, I see it coming.