"The real character of the so-called centrally planned economy is well illustrated by a quip I heard several years ago by Soviet economist Nikolai Fedorenko. He said that a fully balanced, checked, and detailed economic plan for the next year would be ready, with the help of computers, in 30,000 years. There are millions of product variants; there are hundreds of thousands of enterprises; it is necessary to make billions of decisions on inputs and outputs; the plans must relate to labor force, material supplies, wages, costs, prices, "planned profits," investments, transportation, storage, and distribution. These decisions originate from different parts of the planning hierarchy. They are, as a rule, inconsistent and contradictory to each other because they reflect the conflicting interests of different strata of bureaucracy. Because the next year's plan must be ready by next year, and not in 29,999 years, it is inevitably neither balanced nor rational. And Mises proved that without private property in the means of production, even with 30,000 years of computer time, they still couldn't make socialism work."
January 1, 1970
https://en.wikiquote.org/wiki/Economic_Calculation_in_the_Socialist_Commonwealth