Think about a person who works a 9-5 job and is paid by the hour. Would you say his current job is financially efficient? I do not think so, mainly because the amount of his salary is a direct function of how many hours he puts in. And the constraint is: There are only so many hours he can work his job every day.
Now think of a salesman who earns his living selling cars. Sure, he can earn a lot depending on the demand of the cars and his commission per sale but lets face it, he can only sell so many cars per day. Also, once he has sold the car, he is paid a defined amount of cash, with no recurring payments.
