What is the primary cause of market failures when a single company dominates an industry and restricts competition?

The primary cause of market failures when a single company dominates an industry is that this company can control prices and limit choices for consumers. When there is no competition, the dominant company might raise prices higher than they would be if other companies were competing. This situation can lead to lower quality products because the company has less incentive to improve its goods or services since consumers have no alternative options. For example, if a single company is the only provider of internet service in a town, it can charge high prices and offer poor service without worrying about losing customers. Overall, this lack of competition harms consumers and can lead to an inefficient market where resources are not used effectively.