To maintain profits in the long run,a monopoly must be protected by barriers to the entry of other firms into the industry.

Barriers To Entry

Obstacles that make it difficult for new competitors to enter a market, such as high startup costs or regulatory requirements.

Monopoly

a market structure characterized by a single seller who has exclusive control over a product or service, often leading to higher prices and less competition.

Long Run

In economics, a period in which all inputs or factors of production can be varied, allowing companies to adjust all aspects of their operations.