The reason why a purely competitive firm can only maximize its economic profit through an adjustment in output is because they are price takers.
A purely competitive firm exists in a market where they don't set the prices that their goods are sold at. They are therefore price takers.
This means that the only way they can make more economic profit, is by increasing their output so that they can sell more.
In conclusion, it is because they are price takers.
Find out more on being a price taker at https://brainly.com/question/26723154.
