"Whiskey in the Jar in the 70's would have undoubtedly introduced many pop/rock listeners to a traditional song"
Did it, certainly not in the long term (see my posting above); and why should it? Nor, IMO, has any of the other 'users and abusers' who have turned to folk music when their imaginations ran dry.
he only interest Rod Stewart's Wild Mountain Thyme generated was a scramble to copyright the song.
There is no evidence whatever to suggest that the pop treatment of any folk song has attracted anybody to the music any more than Delius's and Vaughan Wiliams's.
Jim Carroll