... like much of the modern American infrastructure* being constructed during the 1950's;
communication technology was considered vital to National Defense. This meant that the Pentagon often underwrote and financed much of the research and construction. Unlike copper wire, which had a tendency to melt in an atomic fireball, radio waves could zoom important orders from point to point unhindered by the carnage. If tower number 37B was replaced by a giant glowing crater- no problem: just reroute through tower number 37C!
... like all Cold War technology it was part of 'The Race'. Early and middle 1950's tech was based on an Atomic War fought with fission weapons in the Kiloton range. With the development and deployment of Hydrogen Bombs and the thousand fold increase in yield the effects of Electomagnetic Pulse (EMP) and high fallout levels made other new technologies and tweaks to the infrastructure necessary.
* the Interstate Highway System