The animals in Animal Farm could not ever achieve a truly equitable society. There were too many inequalities between the animals for this to be possible; many animals could just not physically or mentally handle the load, and were left behind in ignorance. Animal Farm is a satire on real life events dealing with communist Russia, and many of the main characters are impersonations of real life Russian leaders. While the human race today does not live in an equitable society, we do have the potential to achieve it. We possess all the tools and resources to work towards this, unlike animals in general, and the animals on Animal Farm.
For one thing, the animals on Animal Farm were not of equal intelligence. Most animals simply could not comprehend or keep up with the ideas of the pigs, and the ones who were smart enough to even suspect something, were too small in numbers or overmatched in other ways, and could not do anything about it. Many of the animals could not even read or understand the alphabet. The pigs would use fancy language and come up with elaborate accounts of their actions to justify decisions and changes. These explanations might not have satisfied the other animals, but they were either not smart enough, or unable to go against it. The pigs started with small changes and gradually worked their way up to huge ones as they continued to get away with them unopposed. Eventually it got to the point where they changed the seven commandments to just one, and got with it, because there had been so many different changes, and explanations and alterations of history, that no one knew the truth anymore. The pigs were very smart in that they built Napoleon up to be a type of godly figure, and Napoleon's word was really the law. For instance, at one point the pigs were trying to make Snowball out to be a villain, and they were discounting everything that he had done in the beginning, even his heroism at the battle of the cowshed.