There’s also just a fundamental problem with planned economies from a purely economic standpoint: they are much less efficient at actually providing the minimum set of goods and services required by a population, and they’re worse at achieving growth. See the most recent Nobel Prize in economics for a citation. Funnily enough, the same paper’s arguments apply equally to oligarchic economies and crony capitalist economies, which are semi-planned economies by a small group of the ultra wealthy.

More specifically to the OP, communist countries have planned economies, which by nature requires a strong authority to tightly control production. Hence why communist states always have very consolidated political power structures. And once the power is consolidated, all it takes is one bad actor to get that power and ruin everything.