The Medium Ain't Always The Message
In the sixties, listeners tolerated the drifting and multi-path problems (a serious issue in hilly areas like, say, San Francisco) to embrace a newer, hipper, more politically aware brand of rock and roll radio on small-signal FMs...
In the eighties, listeners willingly sat through ten-minute spot breaks to hear what "How-weird" and his motley gang would say next...
In the nineties, listeners turned back to AM, crackly, staticky AM, to hear a guy with a funny Dutch name give voice to their frustrations...
Radio ain't nothing but a means of conveying the message. Give 'em a message they want and they'll go through hell to hear it.
It's that simple.