I think Parenti said it best, in Blackshirts and Reds:

During the cold war, the anticommunist ideological framework could transform any data about existing communist societies into hostile evidence. If the Soviets refused to negotiate a point, they were intransigent and belligerent; if they appeared willing to make concessions, this was but a skillful ploy to put us off our guard. By opposing arms limitations, they would have demonstrated their aggressive intent; but when in fact they supported most armament treaties, it was because they were mendacious and manipulative. If the churches in the USSR were empty, this demonstrated that religion was suppressed; but if the churches were full, this meant the people were rejecting the regime’s atheistic ideology. If the workers went on strike (as happened on infrequent occasions), this was evidence of their alienation from the collectivist system; if they didn’t go on strike, this was because they were intimidated and lacked freedom. A scarcity of consumer goods demonstrated the failure of the economic system; an improvement in consumer supplies meant only that the leaders were attempting to placate a restive population and so maintain a firmer hold over them.

If communists in the United States played an important role struggling for the rights of workers, the poor, African-Americans, women, and others, this was only their guileful way of gathering support among disfranchised groups and gaining power for themselves. How one gained power by fighting for the rights of powerless groups was never explained. What we are dealing with is a nonfalsifiable orthodoxy, so assiduously marketed by the ruling interests that it affected people across the entire political spectrum.

To that end, Marx’s conception of Socialism, that being a state run by the proletariat along the lines of a publicly owned and planned economy, has existed in many areas, and does to this day. These are called “AES” states. You’re partially correct in that no AES state has made it to the historical stage of Communism, which requires a global world government and a fully publicly owned and planned economy, but this is a historical stage requiring Socialism to be fully developed first.

I think you would gain a lot from reading some books on AES states, such as Soviet Democracy by Pat Sloan and Is the Red Flag Flying? Political Economy of the Soviet Union. These aren’t “oligarchies,” or whatnot, but Socialism in existence, warts and all. We need to learn from what worked and what didn’t to progress onwards, it’s clear that Capitalism is in a death spiral and Socialism remains the way forward.