If you have any evidence of 'master craftsman', I would be glad to get it, but once again, I won't hold my breath

Okay. Try this, Jim:

There is also evidence that many of them were never even committed to 'hard copy', but remained only in the mouths of the singers.
David Buchan in his 'The Ballad And The Folk' suggested that the ballads never had fixed texts but were remaid on the spot by the singers, using the plot and established commonplaces.
The Travellers, who were universally non-literate (as well as being a major source of our folk songs), made new songs and carried the old ones in their heads.
Even the attitude of rural communities towards literacy was ambivilent, suggesting that the songs were held and communicated almost exclusively orally.

That's evidence enough for master craftsmen for me!