Any song that still means something after 200 years has got to have something going for it. I've written a (very) few songs, sing a few modern ones, but mostly trad. I don't think I can judge my own songs - it would only be if someone else wanted to sing one that I would know that it had "worked". I'm still waiting.
A song isn't a folksong until someone other than the original writer starts singing it. (that's not intended as a definition of "folksong").
So we who interpret other people's songs are a vital part of the folk process.
Scary or what?