Developing the point picked up above by Musket, as to my use of the concept of "the traditional idiom" in relation to Seth Lakeman:-

The five songwriters I had mentioned in that Cambridge Guide entry were all ones who had a firm background of experience as singers of traditional song; so that their own compositions were inevitably influenced by this, and fitted thematically and stylistically into the sort of music we are engaged with here. Other singer-songwriters "adopted" by 'the Folk Scene' [to employ a useful idiom which I am sure will make the necessary communication as to my meaning to anyone reading posts on this forum] might not have had this background or experience, and so would IMO be less qualified to have their work accepted in the terms implied by the title and topic of this thread.

I think this an essential distinction to be observed in seeking to answer the question which forms the thread title.

≈M≈