This is true. The issue is that already a relatively small nuclear weapon is perfectly sufficient to wipe out most to all civilian structures. However, it does so in a roughly circular area, and you need to increase the initial explosion a royal lot to increase the devastated area by a bit. And as you increase the overall spherical blast of the weapon in order to increase the circle of doom on the ground, more and more explosive power just vaporizes air.
That's why MIRV was introduced. One ICBM delivering 10 - 20 small warheads result in much greater devastation than an equally heavy warhead in one package, because less power is wasted on air and space.
That's why MIRV was introduced. One ICBM delivering 10 - 20 small warheads result in much greater devastation than an equally heavy warhead in one package, because less power is wasted on air and space.
It's morbid math, but it makes sense.