I'm not into violent revolutions. I want to see the poor have a better life and I want to see some fairness, but I don't want to go around killing the rich just because they're rich. I may be a lot of things, but I'm not a murderer.
"The Revolution is not a social dinner, a litterary event, a drawing or an embroidery...The Revolution is an act of violence by which one class overthrows another" - Mao quote from the beginning of the Sergio Leone film "Duck! You Sucker".
In general I think they lack proletariat.
Also from the same movie:
"Don't talk to me about Revolutions I know all about Revolutions...the people who read the books, they go to the people who don't read the books and say it is time to have a change yea, so the poor people make the change. Then the people who read the books sit around their big polished tables and talk and talk and eat and eat, but what has happened to the poor people? THEY'RE DEAD!!! That's your Revolution!
And then what happens? The same fing thing starts all over again"
Leone was rather a "cynic" by that point.