You're right that very small communities tend to a natural form of "socialism"; even Conservatives these days sing the praises of "communities taking care of their own". But it works that way at very small scales because everybody knows everybody else, or in somewhat larger communities, everybody is connected to everybody else by from zero to one or two degrees of separation.

That natural "socialism" can't possibly scale up to the size of a nation, even nations as tiny as those in Scandinavia. I seriously doubt that every Swede knows every other Swede. What seems to happen is that people scale up those informal social arrangements by formalizing and institutionalizing them through the instrument of government, to create a community on a large scale. It can never be quite as personal and cozy as a true village community, but to me it seems better than giving up and just declaring that "it's a jungle out there". After 10,000 years of human civilization, it's fair to say that it's a jungle only if we choose to make it a jungle. Everyone has a choice, and I think the Scandinavians have made a better choice than we have.