By definition, if a company has significant market power then they are not delivering the services/goods society wants from their market. Because they are able to set price they are setting output below optimum. This leaves demand unmet. But the worst part is it creates wasted goods. Ie they wind up making units that they won’t sell or hoarding resources that then may not be used by anyone. Market power leads to inefficiency and that’s supposed to be what free economy does better than the other resource allocation systems.