DPRK- 1945-53.
Cuba- 1956.
China-1949.
Vietnam- 1975.
the USSR- 1917/1925.
"Over 50 revolutions that took power throughout the world for at least a year."
Burying the lede there. Where are those 50 revolutions now? If you answer that question honestly, you admit to p-hacking.
Zero sustained victories in the past 50 years. That doesn't mean it can't happen, though. Which is kind of my point. When Lenin was writing those works, there was no Marxist party that had ever seized power, and even republicanism was looking like a special case. Human relations weren't a "solved" problem then, and they aren't now.