Good point.
It was quite a phase, and accounted for a lot of good movies and books.
Even in nuclear apocalypse literature, there were optimists and pessimists. I liked "Alas Babylon," "Lucifer's Hammer," and other books where humanity copes and moves ahead. I hated "On the Beach," where humanity basically just curled up and died. The movie "Testament" made me nuts.
All that's gone now, mostly. It's almost like the imminent doom of thermonuclear war never hung over a generation. I personally think that alone is one sign that the world has improved.