Just read an awesome essay on the Scholar's Stage comparing @peterthiel 's and Vaclav Smil's differing theses on technological stagnation.
I'm wondering whether nuclear weapons could have been the turning point between technological optimism to risk aversion?
Nuclear fission is the first general purpose technology that has clear, obvious, and potentially immediate, existential risks associated with it.
Well worth reading the full essay: https://scholars-stage.org/about-the-author/