The only time we think of walkability is in big cities but what if suburbs proposed this radical idea of building services that people use closer to where those people actually live. If your day to day is dropping your kids off at school, going to the grocery store and gym, and then work, why in the hell did we decide that your home, work, grocery store and gym should all be in segregated parts of town where the only way to get from one place to another is an expensive hunk of metal.
Because we decided to prioritize things like peace and quiet, distance from people and outdoor spaces for play, cooking and recreation above not leaving a tiny bubble for your whole life.
Living in tiny condos sucks and isn't for everyone, this is the tradeoff we've chosen.
That said, I'd much rather have my kids walk to school in a suburb than a dense urban area.
I think a better approach here is to focus on the supply side of things which is completely driven by companies that want people in the office and the offices are in SF or Palo Alto/Mountain View etc. So the answer here is either allow remote work and encourage people to leave California, or break up the head offices and move them across the country into less expensive areas.
Before the tech boom houses would go for $500-600K in San Jose(I should know as I bought a place in 2013 for $550k) so this high housing crisis is totally artificial and recent. It also doesn't help that having a million+ engineers/tech employees making $200k+ a year all crammed into one geographical region which is constrained by water and mountains.