History is god damn hard. That's why it's useful to read the source material whenever possible.
I don't know how many times I've seen The Parable Of the Cave being used, but reading The Republic, really makes you understand what Plato meant with that story.
It's hard for most people to read that stuff though. I've only scratches the surface. It's easier to trust others to donor for us and distill the information.
And in each century, the lessons learned from the same material may be different too.