That doesn't sound like a terribly good argument -- the fact that it would take O(something big) time to compute something exactly isn't terribly important if you can compute a decent approximation in O(something small) time.
(I'm not a Communist, FWIW.)
My model of how to approximate the optimum solution - specifically, break it up into tiny pieces and keep track of price-analogues by means of a real number valued function of the industrial output being managed - looks an awful lot like a free market with really weird labels for everything. It goes up to and includes closing sub-units that detract from overall optimization (read: unprofitable firms).
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.