How do you call a system of government that by definition does not operate in a free market of ideas, respects individual freedom and property rights and consists of a
monolithic political ideology?
>"Only defeatist quitters speak in such absolutes."
Can you have a system that does not conserve energy? No, there such things as absolutes.
Communism besides being the mother of all bad ideas and the most vile ideology humanity has created is also deeply internally flawed and essentially ensures that it's final outcome can never be reached.
And even if we take that final outcome as our starting point it has no mechanism to sustain itself once there is no government and now laws that dictate social behaviour anyone can do whatever they want and no one can stop them.
So if at T+0 we have the withering of the state and perfect communism at T+1 nothing would stop me from taking control over whatever resource I want and saying well fuck you now you gotta pay.