Currency is a motivational tool for people to get rewards for their hard work. If someone doesn't get any reward for their work, why should they do it? Human brains work on a reward system, and money becomes a learned motivator so it therefore becomes motivation if money is a reward for a task.
Fallacy Of False Cause
Hard work does not always equal a prosperous society.
If every human was polled "Is the taking of a life immoral?", almost all of them would say that it is immoral.
Appeal To Belief
This claim is purely based off of assumption, along with the consideration that even if such a poll was conducted with the predicted results, a large group that has reached consensus does not mean the answer agreed upon is correct.