O Brother must be folk music because lots of folks are listening to it!As Groucho Marx once said, if you analyze humor it ain't funny!
I actually enjoyed the O'Brother movie and found it very funny. Of course it isn't meant to be taken seriously!! "Save your money" and "find the original sources".... please! Hopefully people will be intrigued by the music to search out the source. Why save the music just for classrooms - let people enjoy it for what it is meant to be -sung! I am shocked that people take exception to having these songs performed again. These aren't museum pieces - they are meant to be kept alive. One person's parody is another person's joyful interpretation.
I really get a kick out of people looking for "real" folk music. It is probably on a shelf next to the Holy Grail.