You left out the most important reason. The alternative is socialism which will eventually control everything in our lives. Do we want to be free individuals who choose what we want or to be cogs in a machine and be forced to do what the authorities want?
It eventually comes down to this choice. Do we have a capitalist system with a free market run by the free choices of consumers and producers or a socialist one where decisions are made by authorities enforced by guns and penalties?
Add that without market prices, it is impossible to determine what the consumers want on a timely basis if the power seekers actually wanted to.