One big reason that CA has a reduced housing supply (therefore higher housing price) is https://en.wikipedia.org/wiki/1978_California_Proposition_13
The retired people who brought their house in 80s/90s can stay and hold onto the house for much longer, since the property tax is very "affordable". Whereas in other states, the property tax will push people to move to cheaper places during retirement years, thus increasing the supply to the market.