I agree with your exegesis, Mike. Perhaps Llewyn is in purgatory. Perhaps he has been cursed by Roland Turner (John Goodman). But each time through, things get a little better for him. This time, for instance, he doesn't let the cat out! And he's able to sing "Dink's Song" at the Gaslight and truly bid farewell to Mike, his dead partner.

Maybe next time, he'll be able to take that exit to Akron and see his child.

Interesting that Roland Turner and his "valet," Johnny Five, are representatives of those things that influenced the folk revival but finally had to be put firmly at arms length: jazz and the Beats. Jazz just get you high on heroin, and the Beats just get you arrested for no good reason...