People like to say "show me a communist (or socialist, used interchangably) state that hasn't failed" like some sort of gotcha. My comrade in labor, when have they ever been allowed to just do their thing?
Basically every radical left attempt has been met with staunch opposition. Sometimes local/regional (Spain, Zapatistas), sometimes wider (CIA interventions in... everything). So there's eventually a decision point – what's your relation to violence and oppression. The Soviet Union says "violence is the only way to carve out a place in the world" and becomes a totalitarian empire. A shit outcome.
But if you don't establish strong military backing, you probably go the way of Allende in Chile. (Ousted and killed/forced into suicide by the right-wing aligned army.) Also a shit outcome.
Which is to say it's not "real communism hasn't been tried", it's "real communism hasn't been allowed to be tried".












