WNYC's On the Media ran a great six-part podcast/broadcast series "The Divided Dial" about radio, its reach and significance, and of course the increasing polarisation of the medium:
Several times the point was made that radio is cheap, is accessible by virtually anyone, and in particular is effective at reaching rural regions and those travelling (often in cars or trucks), whether commuters, on-site work (construction, farming, etc.), or transportation work.
For many such audiences, radio is largely the only effective means of reaching them.
<https://www.wnycstudios.org/podcasts/otm/divided-dial>
Several times the point was made that radio is cheap, is accessible by virtually anyone, and in particular is effective at reaching rural regions and those travelling (often in cars or trucks), whether commuters, on-site work (construction, farming, etc.), or transportation work.
For many such audiences, radio is largely the only effective means of reaching them.