Central planning is the ultimate version of monopoly. It is what happens when a single company owns the entire country and no longer has to compete for anything. It is the only employer and the seller of goods, for every good. They banned the import of other goods, so they are all you get. Also they make the laws, so you can't even protest without having tanks moving you down.
"I really hate these corporate overlords, what can we do to fix it? I know, what about giving the corporate overlords all the power in the entire country? Yeah, that will fix it!"
Central planning fails to give the little people what they want. Walmart's central planning is to ensure the profits continue to flow up to the share holders. The workers are expendable, and get a bare minimum the profits (as wages).
Central planning in a communist regime is exactly the same - it enriches the regime, at the expense of the people.