The evolutionary process is painful, but it's the way new things come into the world.

Not all songs are folk songs, or ever going to be folk songs. But if a song is in the process of becoming a folk song, that means entering into the oral tradition, and that means variants. (And that is still true, in spite of all the technology and the recording systems and all that). The end result is a song that says more, probably says it in fewer words, and says it better.