For a really simple way to illustrate how bad the USSR central planning was, look no further than some big companies IT shops. Managers not trained in the specific area and very mistrustful / contemptuous of the actual workers giving orders; defining process and schedule; and telling the workers what "best practices" is. Now, imagine this crud applied to farms and factories.
I am suddenly reminded of Paul Samuelson and his economic textbook touting the idea that the Soviet economy will surpass the USA's economy. Of course, it never came true.