The reason an employer prefers a single "80 hour" employee is because either (a) an 80-hour employee costs less than 2 40-hour employees (worker willing to be a

The reason an employer prefers a single "80 hour" employee is because either (a) an 80-hour employee costs less than 2 40-hour employees (worker willing to be abused), or (b) there is a labor shortage (either natural or artificial (lawyers, doctors, dealmakers with connections) so there are not enough qualified/capable staff.