I think that might be wishful thinking.

It is privileging 200 of history verses several thousand years of human history.

Several thousand years of human history in fact argues for their point of tendency towards equality being a natural imperative, and artificially enforced caste systems being unnatural and instinctively distasteful to people.

See Graber's last book before he died: https://en.wikipedia.org/wiki/The_Dawn_of_Everything?wprov=s...