How does George Orwell use Benjamin to give his opinion about why revolution fails?

Benjamin

The donkey. He is the oldest animal on the farm and stereotypically stubborn and crotchety. He is also intelligent, being the only animal (aside from the pigs) that can read fluently. He never laughs, preferring to make cynical comments, especially the cryptic line, “donkeys live a long time.” Despite Benjamin’s unfriendly nature, he has a special affinity for Boxer. The Rebellion does not change Benjamin’s personality, although he eventually helps the animals read the lettering on the side of the van and the maxim that replaces the Seven Commandments. Benjamin represents the human (and also stereotypically Russian) tendency towards apathy; he holds fast to the idea that life is inherently hard and that efforts for change are futile. Benjamin bears a similarity to Orwell himself. Over the course of his career, Orwell became politically pessimistic and predicted the overtake of the West by totalitarian governments.