"interesting to see whether in 10 or 20 years time this track will be seen as anything other than a passing curiosity."

I think that's probably an inevitability, as indeed it is for virtually all popular commercial music.
The *ballad* itself will continue to endure perfectly unharmed, quite irrespective of that however.
I feel there is too much emphasis being placed on professional artists making commercial folk in any event. And while their work is high-profile in the media may attract the interest of a fresh generation of enthusiasts, like all popular trends (including that of the 60's revival) it will pass.
I'd like to see more emphasis placed on the value of encouraging and supporting amateurs to take up traditional songs and tunes for themselves, and less on the importance of passing commercial music trends.