[@Dinh AaronMk]

1) Communism generally removes individual incentives. Some people might think this is a benefit, since it eliminates greed and inequality, but it also destroys any sort of incentive to work hard. When you are compensated roughly the same regardless of how much you work, how strong you are, or how smart you are, why would anyone put in more than the minimal effort? Game theory works well here: if 1000 people work hard, everyone is 1000 times better off...until one person realizes he can do the bare minimum and still reap the rewards. Then the second, then the third, etc.

2) Removing private property also removes the incentive to maximize its use. When no one "owns" it no one will take care of it.

3) Prices. Prices are a perfect way to signal supply and demand. It is impossible for a central planner to determine the preferences of each individual in a nation...but free pricing can.

In order to make any of these things work, you need a dictatorship to force people to do so. Not working hard enough? If the people's paradise doesn't motivate you, maybe the gulag will. Supply and demand not right? The government is forced to step in.

The above things may be doable on a small scale, but only if people have the choice to buy in. If you force entire nations to do so, it is going to be impossible to move out of the communist dictatorship; you will always need the force of law to make people not follow the "natural" psychology of supply and demand and incentives. I can't think of any practical way that the state will ever wither away.

Basically, you can eliminate inequality in society by making everyone equally miserable.

TL;DR: In its very nature. "From each according to his ability, to each according to his need" basically guarantees that everyone will work just hard enough to not be thrown in a prison camp and receive just enough to survive.