the simple argument against central planning

Any system where everyone has to do everything right in order for things to work out, is not something I could trust.

I mean sooner or later, the Undersecretary of Bread Allotment will say "Well, I could solve this series of 20 differential equations, but I really was looking forward to playing some golf today"...
and then starvation sets in.

Or, the Water Czar retires, and his assistant (who is also his only nephew) is just really not up to solving all those equations even though he'd really love to. And then millions die.

You basically have to account for corruption and general human failure. It might not necessarily happen, but that sure as hell is the way to bet.