There's a practical aspect of this too. Say you pay 4 drivers $17 an hour and to get the 5th you'd have to pay $19 an hour. The problem is that it's tough to

There's a practical aspect of this too. Say you pay 4 drivers $17 an hour and to get the 5th you'd have to pay $19 an hour. The problem is that it's tough to pay 4 drivers $17 and one $19. They'll talk and eventually the other 4 drivers will demand $19 as well. That's why you see a lot of interview and signing bonuses but less wage increases.