Communism fails every time it is tried because it goes against human nature of constantly comparing yourself to others and trying to improve yourself. You will never do harder work if you can get the same reward for easier work, and you will look for other, less moral ways of getting the bigger reward.
Communism sounds great but it will never work until we have unlimited resources and completely automated labour.
Communism is a bunch of random people climbing on eachothers back and when one gets to the top he is expected to pull the others up. Which is great if he’s a good person but most people aren’t.