https://www.realtor.com/news/trends/swing-states-home-affordability-election/
This is a silly yet entertaining article.
The biggest factor is rural vs urban or population density.
California is expensive because of a few urban counties or metro areas.
And those areas are expensive because of excruciating land use restrictions and other environmental red tape.
I remember hearing before 2020 and covid that land use regulations make housing in California 5x more expensive.