When I studied Plato in college no one mentioned that he and Socrates lives through the Peloponnesian War. That "The Republic" is not some idle philosophy about government types, but an answer to how the war started and persisted over decades. That Socrates wasn't sentenced to death to corrupting the minds of youths, but for calling out the hypocrisy of all those involved in the war.

Nothing has changed. The Greeks are no longer a super power and one day we won't be. Human nature won't allow philosopher-kings.