I’d say Italians, Germans and Swedes have much more in common with each other than with the US. The way of life is slightly different, but the philosophy is the same.

Neither do Californians, Alaskans, Alabamans, Montanans, or West Virginians.

But they all have more in common with each other than Europeans, and vice versa.

As a Californian, I resent the accusation that we have anything in common with other Californians.

Well then, California is california-sized as well, so if that approach does not work for USA in its entirety then perhaps it can fix the healthcare system in California?

Yes, perhaps. That's what California is attempting. Unfortunately social security in US is national, so you can't operate a closed system.

E.g. only Danish people can get Danish social security