As we lose obsolete skills, we simultaneously become more interdependent on other humans, as the web of dependencies becomes more complex. More people need to coordinate action to complete even basic tasks.

With that in mind, preserving communications would seem to be near the top of the list (perhaps just below clean water?) when things go wrong. Radio seems like a good backup -- perhaps even ideal.

So I don't think we should compare radio to just any obsolete tech out there.