"A command economy doesn't need to account for left hand screws being different in different towns. That way lies madness. Instead a command economy says THIS is the screw for the people."
And then you hit the brick wall of reality: that one size DOES NOT fit all. Inevitably, you get complaints of a physical nature, such that "Live with it!" is answered with, "Why don't YOU come and try this?!" Dictating square pegs doesn't work when life gives you round holes.