In the natural gas industry, low average total costs are obtained only through large-scale production. in other words, the initial cost of setting up all the necessary pipes and hoses makes it risky and, most likely, unprofitable for competitors to enter the market.= economies of scale
in order to own and operate a taxi, drivers are required to obtain a taxi medallion.= government-created monopolies
the aluminum company of america (alcoa) formerly controlled all u. s. sources of bauxite, a key component in the production of aluminum. given that alcoa did not sell bauxite to any other companies, alcoa was a monopolist in the u. s. aluminum industry from the late 19th century until the 1940s.= exclusive ownership of a key resource