There’s another, much bigger problem, which is that communism doesn’t work even in theory. The reason has to do with information theory - capitalism is a system that uses negative feedback to correct itself. The price system acts as an information conduit to pass necessary information about the supply and demand of goods and services. So a capitalist economy works more like a massively parallel computer.
In a communist system, control of production comes from the top down, creating informational bottlenecks. It’s also much slower.
Modern economies are extremely complex. Milton Friedman wrote a famous essay once in which he showed that no one in the world knows how to make a pencil. Even something as mundane as a pencil requires the collaborative efforts of people, and each of those people needs to have specialized knowledge. Therefore, if you can put the decision-making in the hands of those people, and create an economic system that rewards and punishes them when they are right or wrong, you are in essence building a very adaptive, fast-responding, stable environment.
Consider what happens when the demand for pencils goes up. Pencil manufacturers respond to the increased demand by raising prices. This forces out marginal users who really don’t need pencils, which helps alleviate temporary shortages. In the meantime, the increased profit of pencil manufacture brings more competition and leads to increased pencil production. This, in turn, puts more demand on wood, graphite, ferrules, erasers, etc. The increased demand for brass ferrules drives up the spot price of brass, which causes the price of other brass products to increase a bit. That in turn causes marginal brass users to use less of it, which helps control temporary shortage. So now brass doorknobs cost more, so people use more glass or aluminum doorknobs. That in turn increases the price of glass and aluminum…
These changes ripple through the system, and production of and demand for millions of different products subtly adapts to accomodate. In the end, the increase in demand for pencils may, through several secondary interactions, cause the price of fish to rise. The exact results are impossible to know in advance for all but the most trivial of changes.
And the beauty of the price system is that the guy who makes doorknobs doesn’t have to know anything about pencils or the demand for them. The price system is efficient because it acts as a natural filter, passing only the necessary information and nothing else.
Now consider what happens when someone with imperfect knowledge tries to manage production from the top down. Let’s say we decide that people should use more pencils. So we order them up, but now there are those shortages of wood and brass. But we’re smart guys and we thought of that and ordered more wood and brass production. But that caused an increase use of woodcutting blades, and there weren’t enough sharpening tools available. So now our wood is lying uncut. So we order more sharpening tools, which diverts production away from knife sharpening. So now people have dull knives, and compensate by using more foods that don’t require cutting. Oops. Now there’s a shortage of fish, and a glut of tougher meats. Never saw that one coming… So now we try to adjust to that, which causes other unforseen problems. Plus, there is a much bigger time lag between action and reaction than there is in a capitalist system, which makes these problems worse.
What you find in practice is an increasingly complex set of rules and bureacracies trying to keep it all going. And all of these people may have good intentions and want to do the right thing, but it’s simply impossible. In practice, what you generally wind up with is a series of gluts and shortages, poorer quality, and an overall lower level of productivity.
This problem doesn’t exist just in communist countries, but is a characteristic of any government-imposed solution. Look what happened to Hillary Clinton’s health-care task force - they started with a simple enough goal, but as they worked through all the permutations and distortions, the plan rapidly grew into a monstrosity consisting of something like 1200 pages of regulations. And I guarantee that wouldn’t have even begun to cover al of the problems once such a system was put into place.