The best nights in folk clubs for me at any rate have been where a combination of eager local singers have been followed by a guest performer whose profession is entertaining with folk music.

The idea of sitting in judgement is really no more than counting bums on seats. People will judge what is folk based on whether it's their idea of folk and whether they will bother turning up again at that venue. I doubt anybody needs to follow the ideas of past generations rather than do their own take. Leave that principle to religions and other irrelevant movements.