If I wanted to be really pedantic I could make a case that recorded music can't be folk music. Folk music implies that, to some degree, the artist draws on a greater storehouse of tunes, lyrics, subjects, chord progressions etc. that have been developed sometimes for centuries before being written down, and passed from performer to performer via the act of performance, and which, ideally, the artist should treat with the curious mixture of irreverence and respect such a weight of human achievment deserves. Note that this definition of folk music extends across all cultures. If someone picks up an acoustic guitar or an accordion or a fiddle or whatever and writes a song from scratch that song really doesn't strictly have anything to do with folk music, no matter if it sounds a bit like folk music or the singer has a folksy twang or whatever.
Saying "definiions of genre change", as if that somehow dismisses the need for discussion and negates any possibility of the original and useful definition of the word in question being argued for and maintained is a classic thought-terminating cliché. You must at least provide a new definition of the word 'folk' that isn't a meaningless, thoughtless marketing term.
