> these misunderstand the nature of a truly traditional artefact.
Of course. But the crux is whether there is a viable oral tradition operating within some "community" that passes artefacts on with continuous alteration, sometimes improving, more often diminishing.
Those who take pop versions of traditional songs as definitive may not know or care what "folk tradition" means, but they know what they like and they don't want to see it changed.
For them, at least (meaning almost everybody, since pedants like us and serious, historically minded interpreters, make up close to 0% of the English-speaking population), there's only one "Tom Dooley" and only one "Shule Aroon."