but they were peripheral at best

Rubbish - as it is today, they were the example of quality that less skilled musicians aspired to.

For centuries, people have knocked nails or pegs into bits of wood to hold stuff together. Anyone can do it to some approximate kind fo standard. It hasn't stopped carpentry existing as a profession, for situations where a higher standard is called for. Ditto baking, cooking, building, farming, fighting, cesspit-digging, clothes-making, etc, etc.. Music is just another one. Just because you put the word "folk" in front of it, it doesn't change anything.

Graham.