The use of the term "tradition" is a slippery-slope. Whose? Jazz has a tradition. So-called classical or art song has a tradition. There are "traditions" and what is trad to a British folk audience may not qualify in other musical areas.

The term "new folk" is oxymoronic in my opinion. Folk to me represents some mass acceptance by a group of people (sub-culture) and can't be manufactured over night.
The songs that people write today in a "folk-style" can be called "new folk" but there is a meaninglessness in the term. "Folk-style" overlaps other styles such as jazz, so-called "country" and "pop music". It becomes a mish-mash. Stephen Sondheim calls it a "piss-tache".

When we get into these discussions, it becomes clear that the definitions are not.

The solution in my view may be that we focus on the artist rather than the material. The material will always be subject to the interpretation of the artist. Each song changes with each performance. Without the vision of the performer, the song has no meaning in and of itself. Even when rendered by a non-professional, it comes to life in a unique way.

I think that one of the most interesting aspects of performing material that is called "folk" is its history. It tells us how the people of past times felt. It's really hard to be convincing historically when writing a "new" song. Some "folk-style" songwriters can sort of pull it off. I think of Jean Ritchie or Woody Guthrie as examples. Ewan would fit into this as well.
Stan Rogers from Canada also. Utah Phillips. Si Kahn.

Still, a song to be durable and sung by the nebulous "folk" would have to be made available through individual performers bringing the song to life. Now, some songs are more accessible and universal in this way.

I don't share the conviction that the music we like has to be rigidly confined to a label.
Go for the song, the performer, the music and leave the hair-splitting to the academic grey-beards that thrive on that kind of thing.

Frank Hamilton