It also matters how productive a person is during those hours. I had a boss tell me that he’d give someone a project/task and after 3 weeks they still had nothing to show, but if he gave it to me he’d have it back in a couple hours. When it comes time for promotions and raises, will it go to the person producing results or the one who isn’t?

People have drastically different rates of output. Longer hours is one factor, since we can assume people aren’t working late just to slack off, but there are people who need to work long hours just to keep up with some more productive co-workers who still head out the door at 5.