In practice, people don't tend to pay people to eat shit without gain. You are paying people to help you. Money gaslights everyone into helping each other, the most selfish people become the most selfless.
Of course, real capitalism is much more complex and much uglier than this fantasy. When certain people end up with long-term control of large piles of money, the whole thing gets distorted. They get to make lots of money on interest without doing anything, and making other people eat more shit for scraps. That's the "capital" part of capitalism.
But the toy world-model that this joke is making fun of, is actually the one core positive aspect of capitalism and brings all the prosperity we have: tricking people into helping each other.
