Statists, of course, would like to have everything shared -- except their power. In free democracies they always demand their share of political power -- and always get what they want. However, once they are in power, they keep it to themselves and demonize the opposition.
The Marxist ideal of Communism is an altruistic collectivist society of the future, in which there will be no need for government, family, or private property. Freed from capitalist exploitation, people are expected to unleash their full potential and create unprecedented material abundance. The selfish notion of the pursuit of individual happiness will wither away. There will be no money, no greed, no deprivation, and, therefore, no crime.
However, since a society can't directly leap from capitalism into communism, Marx reasoned that a dictatorial socialist state would be a necessary transition in order to develop the required material base, help to spread the revolution around the world, and to condition the people's minds by uprooting greed and selfishness (or to eliminate those individuals who can't be conditioned).