Self-interest in the social-services community may be at fault. As economist William A. Niskanen explained back in 1971, public agencies seek to maximize their budgets, through which they acquire increased power, status, comfort and security. To keep growing its budget, and hence its power, a welfare bureaucracy has an incentive to expand its “customer” base. With 883,000 full-time-equivalent state and local employees in 2014, California has an enormous bureaucracy. Many work in social services, and many would lose their jobs if the typical welfare client were to move off the welfare rolls.
Further contributing to the poverty problem is California’s housing crisis. More than four in 10 households spent more than 30% of their income on housing in 2015. A shortage of available units has driven prices ever higher, far above income increases. And that shortage is a direct outgrowth of misguided policies.
“Counties and local governments have imposed restrictive land-use regulations that drove up the price of land and dwellings,” explains analyst Wendell Cox. “Middle-income households have been forced to accept lower standards of living while the less fortunate have been driven into poverty by the high cost of housing.”
http://www.latimes.com/opinion/op-ed/la-oe-jackson-california-poverty-20180114-story.html
I looked up that "supplemental poverty rate" and it does seem to be a thing: