"is he no longer one of 'the folk'?" Ah now, that would be the 64,000 dollar question. To what extent and for how long were Burns, Clare, Hardy, perhaps even Shakespeare etc., 'one of the folk'?

To what extent is my singer/writer of songs about his own life as a farm labourer 'one of the folk'?

My own inclination would be to treat all of the broadside writers from about 1750 onwards as part of 'the folk'. BUT, in my own opinion it is impossible to say with any direct dividing line this person was part of 'the folk' and that person wasn't. There are though those miraculously talented people on Mudcat who can.