I'm with Greg. I like to lump all the pre bluegrass players of country music as fiddlers, banjoists, mountain ballad singers,solo country singers (like Jimmie Rodgers), country duets (like The Carter Family, Delmores), stringbands, and maybe jugbands in the old time category. There may be those on the boarder line of old and new- How about The Louvin Brothers - Stanley Brothers - who else?
Some confusion with folkies may be the genre is so big they don't realise it - but that should be the key to it being so good!