"what is folk can always be boiled down to the simplest delivery." Not even close to true. Old-time folk fiddlers didn't respect each other to the extent that they played simply. Many folk guitarists weren't trying to make sure no one thought they had talent for the guitar that simpler guitarists lacked. Some of "the populace" can play instruments very fast, for instance, just like some of "the populace" can fix engines very fast.

Within oral transmission there were traditional ways to adorn. Within oral transmission there were traditional ways to change music, and whether we call a change "adulteration" is merely a matter of personal taste.

"Real is folk." There's no such thing as unqualified authenticity. Authenticity is always about authentically what.