WA has no personal income tax. Also a bit of a libertarian flair overall, why MSFT is openly defense friendly, which means local government has allowed for building housing everywhere.
There's definitely a lot more land to build housing on in the PNW, despite also having some of the geographic constraints that the Bay does, although it hasn't exactly kept housing costs in check.
Maybe "a bit" of a libertarian flair, but also in many ways the urban areas are arguably MORE progressive than the "old conservative NIMBY liberals" in the bay.