"The fantasy is that it only applies to Folk Music"

SOP, you appear to be the only person making this claim. No one is saying that folk song is any less (or any more) creative or dynamic than jazz or any other music, or that musical ideas are not passed around between musicians in other genres. However the "folk process" is most pronounced in folk music, and moreover is the defining element of folk, by which I mean traditional, music.

Someone reinterpreting a piece of classical music will go back to the score. They may be influenced by other interpretations, but they will not make significant changes to the piece, certainly not to the extent that a traditional folk singer might alter a song, possibly from one performance to the next.

The same applies to much popular music - someone wanting to make their own version will usually go back to the original rather than taking someone else's version as a starting point (not least for copyright reasons).

Even with jazz, about which I know little, my impression of it is that a piece will consist of an established theme around which the musicians will improvise. Again, they will undoubtedly be influenced by other musicians' interpretations, but the starting point is the original theme.

Of course, in all genres there are people who break the rules, or who knowingly make reference to another's version.

The difference with folk music is that in many cases the singers did not have access to the original version, and perhaps didn't have the concept of a "correct" version. They took the version they heard, with the changes and improvements made by previous singers, added their own, and passed it on to other singers, who in turn added their own variations, until we ended up with several widely differing versions of the same song.

It seems to me that there's something recognisably different between that creative process and the creative work of an individual or of composers collaborating together. Not better, not worse, but different.

Glueman, I agree that "enjoyment and understanding does not rest on that one notion" (the folk process), but I don't think anyone is suggesting that it does. It's simply describing the mechanism by which we came to end up with these different versions of the same song. If that's of no interest to you, fine, you can ignore it. I agree there are many other more important reasons for enjoying songs.