I think it's enough that we have more "known knowns" now than 200 years ago. We have an
insane amount of knowledge that wasn't available then.
We have neurology, neurochemistry, neuropsychology, etc. to help us understand human motivations and behaviors.
We have evolution to explain human origins, and evolutionary psychology, while very much in its early stages, to identify the origins of behaviors.
We have physics, materialism, and philosophy to suggest the lack of dualistic free will, which completely alters the way we should view crime and punishment.
And for the unknown unknowns, we have modern understandings of statistics and risk analysis coupled with the scientific method. Bayes' theorem was developed before the founding of the USA[0], and yet still, 250 years later, is not well incorporated into law and political strategy.
So maybe what really drives people hasn't changed, but our understanding thereof really, really has. A lot.
[0] https://en.wikipedia.org/wiki/Bayes'_theorem#History