When answering this question, it is important to distinguish between the pigs and the other animals. For the pigs, the rebellion did bring about their ideal society: after overthrowing Mr Jones, for instance, the pigs have risen to become the leaders of Animal Farm and enjoy all the comforts of human life, like living in the farmhouse, making money and drinking alcohol. Only Snowball believed in creating a utopia in which all animals are equal and he is run off the farm by Napoleon as soon as he becomes a threat to the pigs' power.
For the other animals, their failure is a combination of several factors, of which the greed and the corruption of the pigs are certainly important. But the other animals also lack the intelligence to see through the pigs' propaganda, as shown by Boxer's death at the hands of a glue manufacturer. The fact that Squealer convinces them that Boxer was not slaughtered also demonstrates their lack of common sense: they cannot see that the pigs do not rule for the benefit of everyone, only for themselves.