The problem with communism is specific and economic: it has no way to deal with scarcity. Suppose a Utopian, industrialized communist state existed where there was an anthrax outbreak in cattle, reducing the amount of beef that comes to market. In a capitalist society, each person could decide whether to pay more to keep buying their usual amount of meat and forgoing some of their other familiar purchases, spending the same amount on meat and eating less of it, or spending the money they bought meat with and buying a substitute, like fish or tofu. That's "fair" because each person has to make the same decision about meat.
In a communist society, someone has to decide how to distribute meat. Usually (say) there is a surplus, and the government distributes a generous portion to everyone. Now, however, there is a shortage. To whom do you give the meat? You can give it to the industrial workers to keep them strong and help increase production, but there's so many of them that they will each only get a little bit. You can give it to the children, who need it to grow up big and strong, but that won't have any benefit to society for about a decade or so. You can give it to the soldiers, who must be healthy to defend the country, but if there's no war or invasion then the meat is consumed but with no tangible benefit. Or you can give it to the planners and administrators, who think better on a full stomach and without whom society cannot function. That's the central dilemma of a planned economy. You can only say "From each according to his ability, to each according to his need" as long as their is enough to meet everyone's needs.