A free market can never exist, because the establishment of a market requires social intervention of some kind, without which there could not be a market. The absence of the market, economically, is the law of the jungle.
Capitalism postulates an economic law of the jungle that supposedly exists on its own, but it relies entirely upon the elites being able to control a government that uses tax dollars to pay squads of enforcers and interpreters (cops/lawyers) who establish and protect their concepts of "ownership." Without the police and lawyers to enforce owners' interests, there can be no "free market" as they define it, because what they own can be taken away.
The idea of a free market is circular logic, because the funds to pay for the maintenance of the market can only be generated from the market itself. I.e., tax dollars come from transactions (employment, sales, etc.) that occur within the market. The market exists because government maintains it with tax dollars, and so on. Capitalism as the "free market" theorists posit it is as much a myth as the independent American.
Without "ownership" there can be no "capital" because capital is a term used to describe someone's government-granted authority to direct an investment. The "private" planning in fact depends upon a government/societal grant. For example, without a structure of ownership where police protect, and society recognizes, one of Bill Gates' billion dollar chunks, Bill Gates cannot make the decision to invest said billion dollars in any particular way. He is utterly reliant on society and government to grant him that right.
Like all modern economic systems, capitalism is one of government control. The real question is, who will benefit from that control?
Adherents of the free market pretend impartiality because they do not want to address the real question. Not addressing the real question allows the system to continue whereby governments control the market for the benefit of the ownership class.