Final answer:
In a competitive market, it is false that firms make a positive economic profit in the long run; both monopolistic competitors and perfect competitors reach zero economic profit due to the dynamics of entry and exit.
Step-by-step explanation:
At the end of the process of entry and exit, it is false that some firms in a competitive market are making a positive economic profit. In the context of monopolistic competition, firms can certainly make an economic profit or loss in the short run; however, in the long run, the process of entry and exit among firms tends to drive the industry toward a state where firms earn a zero economic profit. This outcome is grounded in the basic principles of market dynamics, where the entry of new firms occurs if existing firms are making an economic profit, increasing competition, and driving down profits. Conversely, if firms are suffering losses, some will exit the market, which reduces competition and can lead to a rise in profits for the remaining firms up to the point where there are zero economic profits. Therefore, while firms in both monopolistic competition and perfect competition eventually reach a zero economic profit in the long run, the paths they take might be different due to factors such as efficiency and variety in the market.