Under single-payer, CA employers will no longer need to provide insurance for their employees. That money could in some way pay for this. It also makes the idea of a 'gig economy' much more palatable, since people working in short-term / part-time situations will no longer have to go without employer-provided insurance. It could be a source of further economic growth since that makes CA a much more friendly place to start a business.

More centralized healthcare systems also have two arguments for driving down cost - one being that such a system is more effective at promoting timely / preventative care (which is a lot cheaper than emergency care). The second is that such a system can negotiate prices with providers more effectively, and invest in long-term projects to reduce the cost of care, driving down the cost of healthcare overall.