The existence of coins does not imply a capital-based society, in the same way the emergence of personal computers in the 70s does not mean the economy of the 70s was highly computerized.
Check out David Graeber’s Debt: The First 5000 Years for some anthropology on how exchange worked in early societies. Trading currency for goods or services was the exception, not the rule.
Why shouldn’t there be a safety net for all?