I'm immensely skeptical of the notion that clever people are needed to tell dumb people what to do to achieve what they want; to "harness the capitalist system".

You 'harness the capitalist system' by participating in it, selling stuff, acquiring resources and exchanging those resources to achieve your goals. (And those goals can be selfish, altruistic or as arbitrary and nonsensical as you please.)

I see little hope for centralized harnessing by clever people

That is the position that I was "sure was not mine".

I say the marketplace and the economic engine behind it are out there, ready and waiting to be exploited by anyone with the ambition and competence to do so. It is a tool which can be used to translate whatever comparative advantage you have into the most efficient goal-maximisation that you can manage.