Plot summary depends on band and age group demographics:
AM band: Male listeners 50+ suffer increased heart attacks / strokes when talk radio doesn't talk.
Canadian FM band: Automobile and truck repair workshops grind to a halt, as there's no Trooper or Chilliwack on Geezer Rock.
Any station airing NPR: No more longform pieces featuring the sound of a cook scraping beans and rice out of a pot. Narrator translates over the cook speaking in their native tongue.
Sports radio: The silence is golden.