Kongo Gumi, the world's oldest continuously operating family enterprise, has closed its doors after an astonishing 1,428 years in business. Libertarian caveat: Until the 19th century it was subsidized by the Japanese government.
Business Week notes the secrets of the firm's success:
How do you make a family business last for 14 centuries? Kongo Gumi's case suggests that it's a good idea to operate in a stable industry. Few industries could be less flighty than Buddhist temple construction.
Flexibility helps, too. During World War II the company "switched temporarily to crafting coffins." I suppose you might call that an indirect government subsidy.