Is the main reason the were Marxist revolutions in the past in places?

Question

like China, Cuba, Vietnam--historical forces, regime decay, challenge from below, poverty, war?

Answer 1

Basically, people will complain about a great many things they don't like about their government, but they won't act unless they are hungry, without shelter or dying due to neglect. So poverty plays a large role, the largest.

Answer 2

Russia, China, Vietnam, and Yugoslavia the communist takeover was in the aftermath of wars which left the ruling powers weak and discredited. In Latin America long term inequality in wealth and income makes if fertile ground for populist revolutionary movement from the left which are sometimes communist as in Cuba, Nicaragua, and Chili.

Answer 3

All those places had marxists financed and supported by Soviet Union as part of the Cold War.