The problem with Communism is that all work and productivity has to be centrally controlled. This puts a severe limit on productivity. In addition, to manufacture anything, all paperwork, if not the parts, have to be shipped through the central control region. Even if your product has all its components made in one area, those components have to be shipped to the controlling center then shipped to the assembly line. No improvements are allowed.
To buy a science fiction paperback in Russia required standing in three, if not more, lines before you could walk out of the store with your purchase. This was true for all purchases in any government-sponsored store; all other trade was illegal.
/BAH