Bruce, that's an excellent theory - nay, that is a truism.
However, Folk Wisdom, when recorded, becomes cast in tablets of stone & ceases to develope. The more it's cast, the worse it gets.
So we are in a cleft stick where the richness of the material can only be preserved in these current times by noting it down, but the very act of doing so damages the thing.
Just think of how many songs are noted in collections (both written and recorded) which never see the light of day in live performance.
I think (let's be contraversial) that I do not want to know the source. When I ask for a song I've heard someone do, I want THEIR version of it - not the source. If everyone learning a song refers to the sourece ( or to a "good" or "famous" recording) then the song will cease to develope & so will the tradition.