Traditional folk songs were all written by singers/songwriters.

A kind of Darwinism may have let the best survive. Some of the more obscure ones, may have been best kept obscure. A lot of music hall songs have now entered into the folk tradition as well.

I can't speak for the music, but the starter of this thread has a valid point on this matter. How can a tradition evolve, if people are clinging in the past, to an ideal that probably never existed in the first place?