The problem is that, apparently, abusing people wholesale is profitable.
Drug dealing is profitable. Chattel slavery was exceptionally profitable. To allow profitability to be our measure of permissibility is to sacrifice civil society at the altar of enterprising tyrants. Economics should never be a substitute for ethics.
The hard part is that I'm not sure any other system really fixes this flaw. Sure, you can be less democratic and give fewer people what they want, but for some reason few people want to live in autocracies of any stripe.
And it's not always clear that there is a solution when the things people want are too diametrically opposed, either. I'm not sure many people would be happy with any of the solutions from "Three Worlds Collide" for example (a short story you can go read online if you don't get the reference).