> [1] - How humanity bounced back from that so quickly is something of a mystery to me.
There is always the "it wasn't as bad as in Mad Max/Fallout/..." explanation. Nuclear winter is now understood to be either less severe than predicted back in the 60s, or nonexistent. Nuclear weapons will kill people and destroy cities, but if they aren't aimed at people or cities, but at military installations such as the US nuclear sponge[0], death toll and destruction will be far less severe. Things like the Golden Gate Bridge or the Eiffel Tower might be left standing, as seen in a few Star Trek episodes. Which would also mean that humanity would be in less of a severe turmoil than other nuclear war SciFi might have imagined.
[0] https://www.reddit.com/r/nuclearwar/comments/18e01zh/would_t... https://www.thomasnet.com/insights/nuclear-sponge/
> Nuclear winter is now understood to be either less severe than predicted back in the 60s,
Back in the 80s. In the 60s it was just megadeath, with a chance of mutants.
(The Krakatoa movie was in 1968, but the winter thing took a while to sink in)
https://en.wikipedia.org/wiki/Nuclear_winter <- look at "Early work".
But you are right that the concept was only made popular in the 80s, and a lot of the earlier works were classified or unknown and obscure to the public.