Through hyperbole, you imply that he's overpaid by market forces. If he manages 20.000 people and increases productivity by just 10%, he'd be worth 2.000 "normal guy" salaries. So a 100 factor doesn't seem far fetched to me.
What strategy would you suggest to arrive at a better price for his work?
To calculate the market price you have to know about the competition. Is there someone else who could increase productivity by 9.99% but request only half the salary? That person could be better for the bottom line.
What strategy would you suggest to arrive at a better price for his work?