Nobody cares how many hours you work. The only thing that matters is what you produced from your work. It is absolutely fair for someone to earn 20 million a year and someone else 20 thousands if the first guy is a thousand times as productive, or what he produces is a thousand times as valuable.
So you think the top banksters who have been bailed out recently are very productive? You are right that there can be such a measure but shouldn't it be in what they did for society?
The US president earns something like 500k dollars a year right? That's legit because he has so much responsibility compared to the average worker. But how does that compare to a manager earning 20 million?