I've always found "folk" to mean "unadulterated" and "unadorned".

If I sing the Springsteen song "The River" straight, because it's a good song and resonates with my experience, that's folk.

If I'm putting on that it's great because I'm from NJ and he's a star and I'm giving my best "earnest" imitation of the man, then it's bullshit.

If I have a natural tremolo/warble/whatever to my voice when I sing, that's folk. If I force myself to sing with, or without, those effects because they're more "traditional", that's bullshit, because it's not honestly coming from my natural self.

Folk is common themes delivered in ways that the populace can understand. A bunch of ri-tee-diddly-um-day doesn't mean a thing to a young urban black audience unless you've connected them to the themes running through the song. The problem is that education, at least Stateside, isn't community/folk-based anymore. it's formulated hypothetically, and from the top down, to try to be one-size-fits as many as possible. If education these days was based on relevance rather than on regurgitation, we'd have teachers relating their lessons in ways their students can grasp by identifying commonalities.

Folk music identifies, highlights and celebrates those commonalities. the fishermen of today can relate to "The Shoals Of Herring" because the work is the same even if the technology and sociopolitical times are different in some ways.

The reason the old songs and acoustic instruments still reign as "folk" by definition is because what is folk can always be boiled down to the simplest delivery. The human voice, the simple scale, the rhythmic clap or relatively primitive drum beat. Even rap, when used to communicate truth rather than to celebrate fantasy at the expense of the ignorant, can be delivered, folk-style, with just a voice.

Real is folk. Fake, with the crutches of innovation for the sake of "the new", and adornments to make otherwise trite and useless pablum palatable, is never folk.