What inspires a film, and what shape that film eventually takes, can be two very different things. The original theme can be a basic platform on which to place and juxtapose ideas and arguments - but then those ideas and arguments take on a life of their own.

So it might be that, although DVRs memoirs inspired the original theme and structure of this film, the Coens superimposed their own questions, arguments and ideas on it. I haven't seen the film - I'm just talking about the role of cinema in an abstract way - and may or may not see it. (I generally don't find films about music very satisfying - "Spinal Tap" being the exception!)

Unless a film is billed as a representation of an actual person - Johnny Cash, General Patton, Glenn Miller, etc. - then relating it to an actuality that you think you remember can be difficult and unsatisfactory.