Yes, I'm aware of the anarcho-communist theories. However, just as you described, it's simply unworkable in our world. It would require that most people have an inherently good nature, which even though we try to act like we do, we don't.

And I also think it's still an authoritarian regime even without a state. It would essentially be mob rule, absolute tyranny of the majority. And that kind of system would immediately become a state anyway.

Beyond that it's almost pointless trying to debate economic systems at the anarchist level, because there's no one to control it. We all think it would "naturally" become this or that, but in reality people would organize a number of different systems. And that's fine. This is why I and a lot of people changed the political compass to a triangle.