[mrtksn]

Money is just IOUs, it means for some reason not specified on the banknote you are owed services. If in a society a small group of people are owed all the services they can indeed commission all those people.

If your rich spend all their money on building pyramids you end up with pyramids instead of something else. They could have chosen to make irrigation systems and have a productive output that makes the whole society more prosperous. Either way the workers get their money, on the Pyramid option their money ends up buying much less food though.