I think the point there is actually about money, not productivity. If you're paying by the hour, they're both the same to the employer, but you'll get more from

I think the point there is actually about money, not productivity. If you're paying by the hour, they're both the same to the employer, but you'll get more from the 5 40hr employees. There's a bunch of simplifying that's going on there (overhead per person, etc.), but the basic message is that if companies can only afford so many people-hours, it's hurting the people they don't hire in addition to their own employees.