Martin Carthy actually said that the only way to damage or harm folk music is not to perform it.

Actually it depends on the televised interview you watched. I can assure that my quote is close to what I heard (and the arrangement I credit to Carthy) - the words ignore and survive were there, and anything came up several times.
But maybe he got tired of saying it the same way over and over, let us call it the folk process...... The message is the same.

He also in the same interview said somewhat to the effect "You can have love, rejection, murder, 100 years war and humour, all in a three minute tale - that's a folk song"

"City of New Orleans" may not be quite as extensive, but it does whirl you 100 miles in three minutes - that's a folk song for you............