This graph indicates Marginal cost (MC) and Average cost (AC) curves to obtain customers. AC is increasing because MC is increasing. It is seen that the decreasing return to scale because MC has higher slope than the AC.
Presume firms are maximizing long-run profit, the price is given by the market, and there are no barriers to entry. MC and AC curves are increasing, what is the optimal number of customers?
With above rules, to be in profit, Price must be higher than AC. In addition, the Price must equal to MC for maximizing long-run profit. Because the price is given by the market, it is constant.
In this case, how do optimal number of customers is calculated?