If you both are so busy and "barley" (not homeless barley, but like needing dual-income) can afford living in the SF Bay Area, then why have kids?
Similarly, why live in the SF Bay Area?
Tech experience in the Bay by no means guarantees the ability to find employment outside it.
When it comes to having children, at some point, you decide you're ready and find a way to make it work. We're managing, but we both have to work. We love the area, our friends are here, are careers are here, we're up in the mountains every few weeks enjoying nature, this really is a beautiful part of the country, and you pay for that. Life isn't only about minimizing costs.
Long term, we probably can't afford to stay here unless I win the startup lottery, so we have an exit plan, but for now, we're enjoying this place.
Have you ever spent all day with toddlers? It's enough to make you go mad sometimes, and it also starves you of adult interaction. Chasing little wild humans and occasionally commanding, "No! Spit that out!" isn't really interaction.
You need a support system when raising kids. Traditionally, this has been family, but people move around for work so much in the US, that many of us don't have that support system, and we outsource that to professionals - day care, nannies, co-ops. All that stuff costs money, and so, we both have to work.