Why are you including things which have not yet made it to the Communist stage of development as examples of success of Marxist theory?

Because Marxism isn't Utopian. Marxism isn't a grand idea of a just society, but a theory of historical development. Read Socialism: Utopian and Scientific, this is basic Marxism.

That isn't a proof that Communism is great yet. It's calling the experiment before actually seeing if it works.

No. Communism is not an "experiment." Marx didn't come up with Communism as a grand society to implement, but saw how one Mode of Production gives way to the next, ie how Capitalism monopolizes into socialized syndicates over time, reaching central planning after proletarian revolution.

And I am not quick to call the USSR or Cuba particularly Dictatorships of the Proletariat. They became actual Dictatorships that carried forward the heirachy of the paramilitary organizations that spawned them never ceeding them to the workers councils like they were supposed to do instead creating new dynasties of career politicians....Career politicians of a one party state are not "working class".

1. They were not dictatorships.

2. Cooperarives aren't Marxism.

I suggest reading Why do Marxists fail to create the "Worker's Paradise?" You have an anti-Marxist idea of what Socialism and Communism are. I also suggest reading Blackshirts and Reds to debunk anticommunist myths. I know I recommended both texts, and I know you didn't read them. You really should!