If you own a house in many places in California your net worth is at least a million. That is my diversification problem. My house is 60% of my net worth.
A lot of my California friends (for years I worked for a company that was headquartered in Silicon Valley) sell their homes when they retire, and move to somewhere else - Albuquerque was a popular choice for a while. Washington/Oregon away from the cities (not Seattle or Portland). A few even moved to Mexico - one to the Philippines. Their house is their retirement account.