Well, except there's all kinds of economic theories about how this isn't true: the tragedy of the commons, negative externalities. There's also a lot of evidence that rational actor theory isn't as true as pure economics would suggest. And of course market inefficiencies will distort price signals. And truly free markets have a hard time remaining such in face of large incentives for rational actors to instead engage in rent seeking or other anti-competitive behavior.
But yes, if you ignore all the problems both theoretical and practical with free markets, free markets work best.
But yes, if you ignore all the problems both theoretical and practical with free markets, free markets work best.