but kid-related costs here are also out of control, accredited infant daycare is insane, and you pretty much have to take what you can get into. same with after school care. this alone is >$3k/mo.
CA self-employment tax is nothing to sneeze at either, especially if you're a contractor in an industry that makes having an s-corp unfeasible.
OK, sure, rents/real estate are higher. A LOT higher. But other than that, you're not going to pay substantially more for a car, computer, or any other consumer good in CA than anywhere else. Gas and food are somewhat higher, although some of that, based on my visits to and relatives in CA, seems to be based on more picky eating preferences than inherent logistical problems (but you say you don't do that).
It seems outlandish on its face: you know that a $400K household has to be way above the median, even in Oakland. So how is everyone else surviving?