CA has overspent and high taxed for decades, leaving no room to adjust revenue in a downturn. Furthermore, their tax structure was very heavily top loaded at higher income and capital gains, which proportionally dropped much more in the recession than a typical broader state tax base, savaging their tax base and demanding much higher adjustment than other states face. When your state finances sail on the edge for so many years, you are bound to fall over when a big crunch comes.