The system is not perfectly efficient because humans aren’t efficient. I think the idea is, keeping a market relatively free (with a sane amount of regulation) allows capital to seek returns. This leads to a lot of independent, decentralized value production, like startups popping up out of nowhere because some founders have an idea and attract capital.

The thing is, people who pile up capital don’t have to be efficient with it. They can basically do whatever they want with their money. They can build giant vanity estates, which you could certainly call inefficient — who needs 20,000 square feet for a family of 3? But… we also care about freedom, so we let people do inefficient things. The only difference between rich people and poor people is they have more money so their inefficiencies are louder. But everybody spends money on senseless wants and vanity. Who needs manicures and hair extensions? Arguably nobody. The “poor” spend on vanity too. And we let them because we care about freedom.

If you wanted to implement a perfectly-efficient system, would that mean banning the fulfillment of any desire that wasn’t strictly a need? I don’t think anyone would want to live in such a system.