I don't ascribe to the fallacy of ignorance, in that you're suggesting it won't work because it hasn't worked.
There is no blueprint for communism. If we hold with Marx’s view of history as a matter of interplay between what he calls the base (the mode of production) and the superstructure (the law, the culture, the apparatuses of the state, our morals, and, basically, everything else in human society), then we can’t predict with real accuracy where we are being led by the next stage. But we can talk a little about how we might get there.
No transition in the mode of production has ever been smooth, nor has it been particularly quick. The transition in Europe from feudalism to capitalism took even longer than the director’s cut of Titanic. It had its own vanguard: Intellectuals like John Locke, Adam Smith, and David Ricardo provided instructions for the leaders of the modern state and its partner economy. It’s useful to note that all these stars of classical economics had died before Marx even learned to read. Yet, theirs are the thoughts on which the poorly functioning neoliberal policy of the present still rests. Theirs are the thoughts on which many lives are ended early or lived in blank servitude.