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Basically, here in the United States, my professors over the years have basically told me that communism in Russia failed because it was riddled with corruption and a centralized planning model that was basically and just simply doing too much, and eventually collapsed. Their argument was that a free market, because of its chaotic nature, was more efficient at growing and progressing markets and industry and science, compared to a centralized soviet system that had great industrial production capabilities, but was just simply not efficient, there are the stories of simple industry failures like nobody could buy new shoes, because none were produced that month to meet demand, or other simple consumer items. When the cold war began, they attempted to keep up with American production and engaged in proxy wars throughout that time, which basically made the soviet economy red-line and collapse, plus they were more of an empire and there was great local resistance to soviet rule in each satellite state that fed Russia.
It seems you've answered your own question. My family came from the Soviet Union, and those anecdotes along with other historical accounts make it clear that there was never "communism" in Marx's sense of the term. To say this has become a common trope that "communists" say, but it is nonetheless true. Still, you could look up a couple of sources on how the Russian system worked, so I won't go into detail. Just a few points I want to mention.
For Marx history was based on dialectical materialism, new conditions emerging from material means. Capitalism was the natural outgrowth following feudalism (or rather, following the rise of the merchant, middle class). This meant that, for Marx, a true communist state would have to be capitalist first. Russia attempted to skip this step, depose the king, and launch straight into a communist state. The ludicrousness of this is evident looking back. The large amount of serfs, kulaks, and even unknown, undiscovered populations would be impossible to organize in any meaningful way. I believe, though I'm not sure and I don't feel like searching for a quote now, that Marx explicitly stated that Russia (and I think Germany) was not ready for communism. In fact, America would be the ideal spot for it to emerge.
That being said, for Marx this type of change was meant to be a kind of paradigm shift. Capitalism had become global even by his time (read his articles on India). Thus communism would have to be an international movement. The idea that Cuba can be truly communist while nearby America was Capitalist would not fly. This was also part of the problem Russia faced.
Russia quickly turned into a kleptocracy. The system wasn't run by "each to his need" but by he who could put money in the right hands. It still is.
Not only a kleptocracy, but a genocidal one at that. Throughout it's history it witnessed mass extermination of unwanted communistst, anarchists, kulaks, dissidents, ethnic groups, Ukranians, and frankly completely other random people through the Gulag system. Not to mention the murder of its own soldiers during WWII. Millions died, mostly during Stalin's reign, but such actions preceded and proceeded him.
Finally, all this is not to say they did not have some successes. Considering the state it was in prior to the revolution, you might say that such successes shouldn't be a huge deal, but there were remarkable advances in technology, agriculture, transport, and especially science (think of the space race). These can be partly attributed to collectivization efforts.
Nonetheless, it's not hard to see why "communism" failed in such a place. The organization required would be massive, even if the system wasn't corrupt, murderous, and deceptive.