REAL EXPLANATION OF THE FILM
People really haven't grasped what this movie was about. I'll explain.
The movie is about how it feels to be an artist struggling to make "real" art (as opposed to something that he thinks he can sell) with absolutely no idea whether his work will ever be appreciated or translate into a living. Meanwhile success is actually just around the corner, and all his aimless behavior will turn out, in retrospect, to have been heroic struggling against the odds to make something genuine.
The point of the flashback at the end is that Bob Dylan playing at the Gaslight (which wasn't revealed at the start) completely changes how all the other scenes in the film must be understood. Once Dylan became successful in real life, the entire folk scene in NYC got a huge amount of attention. Llewyn might or might not become super-sucessful, but he'd at least be able to make a good living and be lifted out of purgatory. We can safely assume this because the story is actually based on a memoir by Dave Van Ronk, who did indeed achieve subsequent success - the title is a reference to his 1963 album "Inside Dave Van Ronk".
A few notes on specific scenes from the film:
- If Dylan was already big, the Record Exec played by F Murray Abraham would NOT have concluded that he "couldn't see any money here" after hearing him play ultra-serious folk. The ownership of his back catalog would be contested and he would immediately be offered an advance on future recordings, because Bob Dylan would have proved that something like that can translate for a larger audience.
- If Llewyn had succeeded in getting on a ship of the merchant navy, he'd have missed out on the coming folk resurgence and all his struggles would have been for nothing.
- The novelty song about Kennedy sending people into outer space may or may not be a hit, and we're supposed to assume Llewyn refusing royalties is a mistake at the time of the scene - but when "serious" folk music becomes suddenly commercial, having it on his resume would make him look like a for-hire hack and ruin his ability to sell himself as a real artist. Whether a hit or not, Kennedy is going to be assassinated in less than two years and it will seem tasteless and be utterly forgotten.
- Llewyn is NOT as flawed and misguided as he often appears. The reason he's depicted as such is because he actually buys the perception of Jean that he's an a-hole, even though he's totally committed in his desire to make something meaningful when most around him are not. He's sometimes obnoxious, but he also blithely pays for ALL of Jean's abortion (and has done so before with a previous girlfriend) even though she would almost certainly be at least as able to pay for half given that unlike him, she's not literally homeless.
- The flashback also reveals that the man in the bar DID have sex with Jean, which means that Jean is hardly a saint herself, given that she has apparently cheated on her boyfriend with multiple partners. Yet she is by far the most critical of Llewyn in the film - which calls the whole "Llewyn is an a-hole" premise into question: Llewyn actually cares that he lost the cat - he goes to see his dad and doesn't get angry when he reacts to hearing his music by soiling himself. He's not an *beep* at all, he's just not following the same principles as everyone else because he has a Calling that's more important to him than "just existing".
Hope this helps. I'd appreciate bumping, too many people seem to have not grasped the internal logic of this movie and are underrating it as a result, much like they did with A Serious Man. Like that film, it's seem more or less flawless to me, you just need to understand what it's doing.