"Rock 'n' Roll dates from the mid 1950s"
A mere speck in the cosmos compared to the many centuries longevity of folk song
Folk rock hardly survived a decade and rock n' Roll comes with a compulsory shelf-life date which ascertains that today's rockers with have no taste for what turned on their predecessors and probably no idea
The main difference between the genres is that Trad folk proper was a grass roots movement made, sung and sung played by the people roiginally and revived to escape the commercial pap that was force-fed into us in the mid 1950s you mentioned
Those songs are our songs and the song nearly said - rock in all its forms comes with a price tag for permission to use it
"Does a traditional folk song stop being a traditional folk song if you add bass and drums to it?"
Is Vaughan Williams' 4th Sea Symphony folk because it uses 'The Captain's Apprentice as a musical theme ?
In my opinion, no to either
A fork songs is a performing form with a storytelling function as well as a set of words.
Jim