Industry concentration is very serious in some industry. Once monopoly fall in the hand of private corporation, the public will suffer since profit maximization is the only objective of a private corporations. There are two ways to solve the problem. One is the government control the price movement of the monopoly private corporation, the other is to nationalize the monopoly private corporation to take the price in public hands. Therefore the concept of monopoly just applies to private corporations rather than public corporation. If you look around the world, many public corporation in monopoly situation, need to be in public hands. For example, municipal transit, water supply system, hydro system, airports operation, port operation, education, health care, telecommunication, raiways, you cannot count them all. All these business are in monopoly, and run by government everywhere around the world, nobody complain about their monopoly because monopoly never applied to public business and all public business is in monopoly situation.