The US is supposed to be a "free market" of governments. Don't like the government in California? Go to another state. Don't like that businesses are leaving your state? Vote for someone else.
If you say that losing any businesses -- regardless of the potential benefits -- is unacceptable, then you essentially have a completely stagnant state.
If all the US states are stagnant like that, and there is no innovation in legislation, then we end up with problems that we never even try to solve.
California's economy is not going to die whether this bill passes or not (although it certainly will not).