People need to get a grip. Every 'celebrity ' has a following that they are relevant for, and have meaning for. Expand your minds and appreciate the differences between societies and cultures.
Regarding John Prine, he is definitely a legend in some circles, and has influence far beyond those. Maybe you haven't heard of him, but have you heard of Bob Dylan, Johnny Cash, and Roger Waters? Here what they have to say about him:
Prine is widely regarded as one of the most influential songwriters of his generation.
In 2009, Bob Dylan told The Huffington Post that Prine was one of his favorite writers, stating "Prine's stuff is pure Proustian existentialism. Midwestern mindtrips to the nth degree. And he writes beautiful songs. I remember when Kris Kristofferson first brought him on the scene. 'Sam Stone' featuring the wonderfully evocative line: 'There’s a hole in daddy's arm where all the money goes, and Jesus Christ died for nothing I suppose.'[16] All that stuff about "Sam Stone," the soldier junkie daddy, and "Donald and Lydia", where people make love from ten miles away. Nobody but Prine could write like that."[17]
Johnny Cash, in his autobiography Cash, wrote, "I don't listen to music much at the farm, unless I'm going into songwriting mode and looking for inspiration. Then I'll put on something by the writers I've admired and used for years--Rodney Crowell, John Prine, Guy Clark, and the late Steve Goodman are my Big Four..."[18]
Roger Waters, when asked by Word Magazine in 2008 if he heard Pink Floyd's influence in newer British bands like Radiohead, replied, "I don't really listen to Radiohead. I listened to the albums and they just didn't move me in the way, say, John Prine does. His is just extraordinarily eloquent music—and he lives on that plane with Neil Young and Lennon."[19]
2004 saw Prine's song "Sam Stone" covered by Laura Cantrell for the Future Soundtrack for America compilation.