The economist and historian Dierdre McCloskey put it this way ( my paraphrasing). If some one glanced at what happened in the twentieth century and still believed in the value of central planning, they were not paying attention.
The Marxian dreams and even the subsequent efforts of the market socialists such as Oscar Lange ended badly or sometimes never really got off the ground. Things ended badly in the case of the USSR and Communist China wherein the promises of greater prosperity and equality ended in mass starvation and mass murder.The 1917-1991 gigantic social experiment was a failure.
The contrast between East and West Germany and North and South Korea could not be more striking and devastating to the devotees of socialist planning and their advocates had to find arguments not based on economic success.
The economist Anthony de Jasay in his book Political Economy,Concisely discusses what he considers to be the two last refuges of the socialist central planner;the plea for social justice and the doctrine of unequal exchange.
We can find versions of both in the rhetoric of the defenders of the Affordable Care Act (ACA) and in the pronouncements of the medical progressives whose major premise is that medical care is too important and complex to be left to the individual physician and patient and that we must have wise leaders with ideas to replace the traditional "dyad" of the patient and physician as the deciders of medical care .
."The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design." FA Hayek from The Fatal Conceit