Or capitalism for that matter. This is the trouble with utopian systems like communism and free-market capitalism. Their proponents - Adam Smith, Karl Marx - sincerely believe that if only human beings behaved the way they should do, their systems would run smoothly and beautifully and everyone would be happy.
I think free-market capitalism is the embodiment of unfettered human instincts related to greed and hoarding that were necessary before we evolved from wild animals, but still very present in our psyches.
Communism (as per the writings of Marx) is a clumsy way of trying to frame a path to more altruistic transcending of such instincts in order to allow everyone to share the benefits of productive output.
But then, if not everyone subscribes to the 'sharing fairly' principle, it will fail as a socio-economic model.
Also, we will always start from a position of there being in place a financial elite, who will generally actively oppose any moves to strip them of their privilege, and willing to expend a chunk of their wealth to fight to preserve the status quo, manifesting itself as a counter-revolutionary force.
As we've seen in numerous cases, the response by the revolutionaries has been to impose totalitarianism and oppression in order to block the counter-revolution. Initially noble ideals are cast aside in the name of preserving the revolution. The irony is that such oppression merely fosters antipathy amongst the people the revolution was supposed to benefit.
In many ways, the Cold War was won by the 'capitalists' when the Imperial countries of Europe plus the US armed, funded and even joined the counter-revolutionary White Army, triggering the sort of totalitarian oppression and subjugation of the Russian people that was never part of Marx's manifesto and never part of the plans of most of the Revolutionaries. When Stalin beat Trotsky to succeed Lenin, the mutation of what should have been an emancipating social revolution into a hellishly oppressive totalitarian dystopia was complete.