I see your point 100%. I work for a large oil company, and am a manager. My younger employees tend to put in upwards of 60 hours per week because they see the relation to their hard work and organizational success. They are on fixed salary, with a requirement of 40 hours/week. I have times when I have to force them out the door, even if it means scheduling a happy hour for them, and my picking up the tab. I gladly do so, as I know that they have earned it.
Voluntary or not, I do feel that everyone should show up. In speaking with my employees about why they work so many hours, they say it has to do with fear. They don't want to be passed up for a promotion, or have the next person pick up a skill that they don't have. There are more guarantees where I work, as opposed to pro football. We've all seen multi-million dollar players get nixed at the drop of a dime in football. In my workplace, I've never had to fire anyone in 8 years of management. These players don't have any fear because they have their money in the bank, plain and simple.