Most criticisms of California target public sector backwardness, so it's not a refutation of that to point to the strength of the state's private sector. And "CA's private sector is strong, ergo it hasn't been harmed by the government" is a circular argument. This is an argument over the precise extent to which bad policies are bad. Seems more useful to discuss what genuinely good policy looks like.
The argument that California's policies must be bad, regardless of the fact that they've produced the strongest private sector in the country, is equally fallacious.
California cannot survive without some combination of:
-Huge Spending cuts
-Huge Tax increases (which, if overdone, may result in less tax revenue.)
-Federal Gov't bailout.
You can play cause and effect all you want, but basic arithmetic is really all that matters.