"If you're not an enthusiast for traditional music (and you sound fairly dismissive of the idea of being an enthusiast), then you probably aren't bothered about how much traditional music people are able to hear. I am."

FWIW almost all the 'folk' music in my collection is authentic traditional music, much of it older recordings.
It has almost nothing to do with folk club and leather tankard hobbyist end of the 'scene'. I bought it because I like the way it sounds, not for actual or spurious reasons of authenticity. I dig simple, straightforward music with limited or non-existent production values. Those preferences inevitably put folk music in my sights.

I think you can tell contemporary music that is folk that may - or more likely may well not not be played in traditional modes or instrumentation, by its intentions but a listener has to trust their ears.

I doubt the atomisation of communities prior to the industrial revolution or mass transport or recording leant their music anything wholly exclusive - at least I've never heard any regional form that wasn't at least half some other form - so I'm forced to conclude those divisions are arbitrary. And if form is notional, then why not other accrued values?

One of the problems (for me) with clubs is performers and bookers believe singer-songwriting that resembles traditional styles will be acceptable to its audience. I'd be more well disposed to SS's loops and digital sequences if it had genuine folkish marks than new writing in old styles if it was merely pastiche. It relies on being able to tell and I'm afraid that requires discrimination and - dare I say it - knowledge and taste.