Which revival? There were several. The "professional" didn't really arrive until the appearance of recordings and radio provided widespread accessibility to a general public, but, in the US at least, the first "Professional" folksingers to make it big were the Country singers: Carter Family, Jimmy Rogers, Vernon Dalhart, Carson Robison etc.
And like just about all performers who cater to a widely-varied audience, they pimped upn the music to make it more generally palatable, and added to it the musical values and styles that they heard in other popular music.
    Commercial "folk" music has its own traditions; it has also impinged upon and altered the traditions of social singers/instrumentalists.