well if we are discussing voluntarism a culture would only win by being more competitive than competing cultural identities in the marketplace of ideas. I can't dive deep into social organization currently, but I think Richard Dawkin's "The Selfish Gene" gives a good discussion of cultural evolution. Concerning financing, either a, poor people would be voluntarily subsidized by those who can pay, perhaps merchants have an interest in an NAP culture or other people have interests in such subsidy, perhaps friendly societies or religious groups. Or people could be made poor no more via some sort of a guaranteed minimum income, which in a voluntary society would be funded by people directly and/or by nonprofits that perhaps capture portions of the economy.