Orc and I have gone round and round about this, but basically my feelings are:
Communism didn't work in small scale trials (communal farms)
Communism didn't work in larger scale trials (countries)
Communism wouldn't work in massive scale (whole world)
In theory, it's possible that some day we'll have the ability to pull something like it off, but until there is literally no need for human labor, that time won't have come.
By way of contrast, true Capitalism is problematic because it doesn't allow for compassion. It a true Capitalist economy, there would be no social security nets (like food stamps, unemployment benefits, welfare, governmental subsidies, etc.). It also actively encourages predatory business practices such as monopolies and price fixing.
Revelations is absolutely correct. No theoretical construct, no matter how perfect its construction or initial implementation can survive long against the depredations of human manipulation.
[Necrons]shoot, shoot, teleport, shoot. win