Moreover, in wartime or during some other major catastrophe when technical infrastructure is likely to be impacted or destroyed then establishing and maintaining communications services on these frequencies is easy for reasons that the technology is low-tech and easy to understand—and there's an enormous amount of engineering experience to fall back upon (about 100 years' worth).
That we even have to raise this discussion is a quintessential example of intergenerational information loss.
Given their strategic importance, governments should put priority on educating the smartphone/streaming generation that these other modes of electronic communication actually exist and that they may even have to depend upon them.
I only need to refer to the current debate over retaining AM-band reception in car radios to illustrate the paucity of understanding. That EV manufacturers are pushing for the removal of the AM band in their car radios is proof-positive of how little the current breed of electronics engineers knows about these frequencies let alone their strategic importance.