"isn't this itself an artificial distinction? "
No it isn't Paul.
The traditional singers we have questioned seem to have had an innate understanding and feel for their songs; they grew up with them as part of their lives, the 'wore them' as they would wear a comfortable old jacket (at least, those grew up within reaching distance of a living tradition did).
They may have lost the ability to 'perform' them as they once did, but they never lost the ability to re-live' them.
Those of us who came to the songs as outsiders have had to work to gain an understanding of, or feeling for them - even those who might have heard them when we were young, sung at home.
Sitting for hours on end with singers like Walter Pardon or Tom Lenihan made me realise how close they were to their songs - a closeness that I have seldom, if ever, seen in a revival singer.
If you mean there is no difference and the term revival itself is meaningless - I have said what I believe to be the case elsewhere.
Jim Carroll