I mean it very famously was lol. But ok. I guess that specific period of time where the world lived in constant fear of nuclear annihilation, where schoolchildren were put through drills in school to shelter themselves from nuclear blasts, young men were being conscripted and sent off to war against their will, widespread social upheaval and civil unrest, and a wave of unprecedented political violence culminating in the public assassination of a sitting US President was full of… optimism

Ye,s it was. Maybe you should talk to your parents and/or grandparents about this. Mine lived and grew up in what then was West Germany. When my parents talk about the nuclear drills at school, the fear still returns to their eyes and they gaze into nothingness. When my grandparents talk about the air raid siren tests the trembling in their voices is heartbreaking.
That shit was real and terrifying. And I personally think this constant, everoresent fear was what made stories about an optimistic future such a success.

Oh you must be right then, not the people who were alive at the time and made and absolute shit ton of media about the exact thing you're contesting.