I'm not a fan of the argument that since the Soviet Union and its derivative states (including China) failed that there is no way to accomplish that Marxist utopic vision or that any variation on socialism has to fail.

Russia was the only real attempt. The 1917 revolution was about it, and then the coup by Stalin to overthrow Lenin and Trotsky threw out any shred of attempt to reach any kind of utopia and just turned the country into a dictatorship with a globalist coat of paint.

Russia itself can absolutely be used as an example of the failings of Marxism and Communism, but I don't think any other country can, for the sole reason that once the Soviet Union was established and the Cold War underway neither side was going to let an ideological uprising happen anywhere on Earth in isolation. Every single socialist / communist state from the Eastern Bloc countries that were conquered by Russia to puppet states in the Middle East to sponsored uprisings in South America and Southeast Asia were all done with Soviet support to create Stalin style dictatorships. I don't think for a second that Mao ever thought China would become some stateless utopia where everyone owns everything in public. Mao took power to be a king, in the same way Fidel did, in the same way Kim Il Sung did. And they all did it with Soviet support financially and militarily.

The US were well documented kingmakers in that era too. It is why most of the Middle East has such deeply instilled hatred of the US that they are willing to give their lives to attack the US. The difference is that the Soviets demanded loyalty by labeling yourself a Peoples Republic and modeling your government after Stalin's - the US just wanted puppet states that did what the US said, be they democratic or totalitarian, it didn't really matter to Washington.

But that isn't something that is going to change, either. Revolutions without foreign support always degrade into dictatorships to fill power vacuums when the unorganized hoard of revolutionaries dissipates - France, Russia, and more recently Egypt all demonstrate what happens in those circumstances. The US had a successful revolution only because it was the elite casting off a foreign power with the support of another, and without Frances help or the support of the American aristocracy the US would have never been founded. Internal wars for revolution fail, revolutions without international support fail, and new governments post-revolution that are too "different" from the global status quo also fail because the world powers will cut you off if you don't play by their rules in international trade. And you can be sure almost every government on Earth today with few exceptions function and exist with the blessings of the United States. If anyone tried to overthrow those "for the people" like the Iranian people did to their Shah you can bet the US will have nothing nice to say about the pursuit of liberty if its against American economic interests.

So no, communism doesn't work, but its not because of some tautology that you can never reach this post-state utopia, but more because nobody can change their government in isolation - the influence of foreign actors will always either push you towards their favored ideology or sabotage your attempt. The world is too interconnected now for an upstart band of ideologues to depose the king and try something new.