The theory that groups such as Pentangle and Steeleye draw an audience for traditional song doesn't hold water; what they draw an audience for is their particular take on traditional song.
When Shirley Ellis took 'The Clapping Song' into the hit parade many centuries ago, some argued (including several folk magazines) that this was the big break through - it didn't happen. The same applies to Sinead O'Connor's 'Nua Sean Nós album, which has done nothin whatever for Irish traditional song.
Watering down malt whiskey only develops a taste for watered down malt whiskey.
My 'restricted' definition is restricted by the fact that there is a definition to be restricted by (see 'How Much Folk is There' thread) This is a definition, not a law that everybody must listen to the real thing.
Jim
Ccarroll