Who must accept the blame for the failure of the animal farm? Is it Snowball,Napoleon, Old Major, the pigs, the humans, or all of the animals? What does Orwell want us to conclude?

It would be easy to direct blame squarely on the shoulders of Napoleon. I think Orwell was more subtle than that. I think that Orwell was saying the utopia that communists or extreme socialists seek is unattainable. When incentive to work, freedom to evolve, and individuality is removed: society collapses. Napoleon and his cronies personify the perils of this system.

What are some reasons on why Napoleon is to blame?