I worked for a CNN Headline News affiliate in Albany NY in the 1990s. Around the country, a few dozen AM stations did All-News using Headline News, with their own inserts at various times of the hour. I seem to remember Headline News did light features at :24 and :54 so that's when we did our own local news instead. Then at :00 and :30, the top national stories aired from the network. There were also breaks where our station inserted local commercials and 30 second weather updates.
Even though CNN marketed this to radio stations via a radio syndicator, I thought they were never fully committed. CNN never told its reporters to stop using graphics alone to identify the audio clips in their reports. So reporters would talk about a big snowstorm, and a clip would come on saying "I am sending out crews to plow the roads." Only on TV could you see the graphic that it was Governor John Smith saying this. The CNN reporter didn't say Gov. John Smith in his report.
In many markets, small to large, AM stations are still simulcasting TV audio, not just 60 Minutes or The CBS Evening News. WGN 720 Chicago runs the WGN-TV morning news at 4am. I think it sounds terrible, especially when meteorologists stand in front of a weather map showing us a cold front moving through or sportscasters say "Look at that spectacular catch!" On the other hand, I do sometimes listen to MSNBC while listening to SiriusXM in my car.