At a price of $18 for a haircut, Devon's supply curve indicates that he would supply 1 haircut. However, if he supplied 2 haircuts for $18 each, he would take in a total of $36. His only costs for providing 2 haircuts would be the $10 marginal cost of the first haircut and the $20 marginal cost of the second haircut, for a total of $30. Explain why Devon would not provide 2 haircuts even though his receipts of $36 would exceed his total cost of $30