Re: Fatal Flaw?
No, you could definitely convince me. I've been wrong before. You can search "Children of Men" on my site for a good example where a reader pointed out flaws in my initial analysis. My initial understanding of "The Wrestler" was wrong as well. (As was my use of "Casablanca" as not being an adaptation).
I guess this goes back to my initial reason for popping my head in here: the confusion some writers encounter when they try to write Main Characters who don't drive the efforts towards resolving the story's central problem. Save the Cat! and McKee require that writers write "willful protagonists" - this runs counter to some writer's intuition and runs up against some of the films I provided as examples.
A neophyte writer trying to write "Casablanca" might struggle with the idea that he has a character that doesn't stick his neck out for anyone yet also has to be responsible for driving the plot forward. While you could argue that Rick does some of this towards the end of the film, in the beginning he could care less.
That's why I think it is important that writers find comfort in knowing that they can separate out the concepts of Protagonist and Main Character if they want to. You don't have to. There are great films where they are one and the same (Up In The Air, The Wrestler, Silence of the Lambs, Braveheart, The Godfather, and so on), but there are many who start out writing their story, then find they struggle with who is really driving things and who the audience feels they are.
Understanding the difference between the two opens up a world of possibilities.