I think many people consider nuclear war an end of the world event. Working hard to survive just to be left adrift in the ashes of civilization with likely long-term health effects seems counterproductive to some of us.
Though the standard of living for survivors is sure to plummet, as famine and other secondary problems start to take precedence.
End of the world? No. Set back industrialized society two centuries? Sure.
"Moscow alone was targeted with at least eighty nuclear weapons, and every Russian city with a population greater than 25,000 would be hit by at least one."
And that was the December 1960 plan.