There are some assumptions behind Communism that doom it. One assumption is about knowing the world enough to be able to manage things. Another assumption is on human nature and the wanting to be equal.
The biggest reason that Communism fails is a lack of knowledge. The communist system is built on assuming that the central authority can know fully. This is a false assumption. A centralized economic planning system fails because it cannot know all the local factors that affect the local economy. Workers cannot properly manage a factory because they don't know all the needs of their customers. And on and on.
It is not possible to know all the local issues and how to solve them and know what the future changes will be. 852
Most importantly, it is not possible to know where we need to be investing in order to meet tomorrow's needs.
The Marxist vision of workers running the factories and farm hands running the farms is based on an assumption of slowly changing conditions - changing so slowly that workers and farm hands could know the conditions and needs. However, this assumption massively fails in today's world.
What happens is that in a changing environment, some people will learn about situations before others do and will be able to profit from that knowledge. The most extreme cases today include setting up computers where the information about stock trade requests hit those computers before it hits other computers and being able to change prices and / or initiate other trades based on that knowledge.
The more centralized the planning, the slower it responds to conditions in the world. (For example, there was a study on emergency response teams for cities / states / countries. The more centralized the control, the more people died in the emergencies.)
Economic equality is a noble goal, but it has as an assumption that people want others to be equal with them. That works in some families and fails in others. It works in some tribal groups. But it fails miserably in societies where people do not feel like the rest of society is "like them". It fails when some people feel as if they are not part of society. 998