Topic summary
Profitability

Extracted from the Wikipedia article Profit (economics).
Competitive and contestable markets
The same is likewise true of the long run equilibria of monopolistically competitive industries, and more generally any market which is held to be contestable. Normally, a firm that introduces a differentiated product can initially secure temporary market power for a short while (See Monopoly Profit § Persistence). At this stage, the initial price the consumer must pay for the product is high, and the demand for, as well as the availability of the product in the market, will be limited. In the long run however, when the profitability of the product is well established, and because there are few barriers to entry, the number of firms that produce this product will increase. Eventually, the supply of the product will become relatively large, and the price of the product will reduce to the level of the average cost of production. When this finally occurs, all economic profit associated with producing and selling the product disappears, and the initial monopoly turns into a competitive industry. In the case of contestable markets, the cycle is often ended with the departure of the former "hit and run" entrants to the market, returning the industry to its previous state, just with a lower price and no economic profit for the incumbent firms.