Why should the employment question for salesmen be, "How generous can we afford to be?", when for everyone else it's "How stingy can we afford to be?"? The whole reason a company hires any employee, at all, is because it's profitable. The question is why employees who don't contribute to the core mission of the firm should receive 90% of the revenue they generate, while those who do receive a fixed salary irrespective of revenue (and also have to work long hours and take few vacations).