Richard Rhodes recently gave a Long Now talk called The Twilight of the Bombs about the future obsolescence of nuclear weaponry. From Stewart Brand’s summary of the talk:
How much did the Cold War cost everyone from 1948 to 1991, and how much of that was for nuclear weapons? The total cost has been estimated at $18.5 trillion, with $7.8 trillion for nuclear. At the peak the Soviet Union had 95,000 weapons and the US had 20 to 40,000. America’s current seriously degraded infrastructure would cost about $2.2 trillion to fix — all the gas lines and water lines and schools and bridges. We spent that money on bombs we never intended to use — all of the Cold War players, major and minor, told Rhodes that everyone knew that the bombs must not and could not be used. Much of the nuclear expansion was for domestic consumption: one must appear “ahead,” even though numbers past a couple dozen warheads were functionally meaningless.