Revolution is Hard
I asked earlier why Cuba was still Communist, despite it's widespread global collapse. Most of the big transitions happened because those at the top changed their minds, in Russia and in China. Without the Russian threat, almost all of Communist Europe quickly dumped Communism. In Cuba, where the Castros still rule that is unlikely to happen, at least until they finally shuffle off the stage.
Venezuela is an interesting case. A highly repressive, semi-Communist leadership has produced a catastrophic economic collapse. Will raw public anger be enough to overthrow Maduro? Stay tuned.