California finding a way to go single payer would be an absolute game-changer for the rest of the country.
My family participated in Kaiser-Permanente in SoCal for several years and loved KP. Their rates were far better than other insurers. Their integrated and systemic approach, with all-in care at medical centers seemed like an excellent model to emulate. No coinsurance, no catastrophic max, excellent care and preventive strategies. A family member suffered a major medical emergency with several surgeries, imaging, testing and physical therapy and I thank my lucky stars frequently that we were in the KP system during that period.
Something like KP on a massive scale would be a wonder IMO. I don't live in California anymore but hope they can make it happen, because the pressure for the rest of the states, and the Federal Government, to do the same would become tremendous.