Llewyn was no Dave Van Ronk
I find it incredulous that the Coens' cite Dave Van Ronk as inspiration for Llewyn Davis. Dave Van Ronk was a key figure in the Greenwich Village folk music movement in the 60's and 70's. He was a guru to the likes of Bob Dylan, Tom Paxton,Joni Mitchell and a host of others.
Van Ronk inspired a movement. To infer that ten years after this movie was to take place, Llewyn was expected to have such legendary status boggles the mind. Who in the movie even followed him? His record producer had no respect for his talent. The music mogul in Chicago viewed him as a performer with not much more than intermediate ability.
As far as inspiring others, Llewyn showed little respect for any other performer. He treated Troy Nelson (based on Tom Paxton) with contempt and viewed him as some sort of hick. When Troy, Jan and Jim sang Five Hundred Miles at the Gashouse, he was taken aback when he notice the audience singing along. He shouted obscenities at autoharp-strumming Elizabeth Hobby and demeaned the Irish quartet singing The Auld Triangle to the point that he had to be ejected from the premises. These are not the acts of a great leader and teacher.
Inside Llewyn Davis was a movie of a lost soul stuck in a loop which seemed to have no happy ending. The only similarities between Llewyn and Dave Van Ronk was Greenwich Village and folk music.