Economists sometimes get confused - especially when the real world doesn't fit into their neat boxes.

Network industries like telephone and electricity are today's case in point. Economists have viewed these parts of the economy as requiring special attention from regulatory authorities. They're viewed as "natural" monopolies displaying "economies of scope" and characterized by risky "lock-in" or "path dependency" features. That supposedly makes them prone to abuse by their free-market owners, and therefore in need of impartial regulatory oversight.