I think this is an incomplete picture, though, EJ. While there were a few earnest groups like the NLCR, most of the earnest groups were more like the Kingston Trio, drawing on what the Weavers had done in the 40s. These folks WEREN'T concerned with authenticity per. se., but with gentrifying these traditions into a clean-cut aesthetic that DID happen to be commercial. I would agree that "authenticity" was a structuring principle of some revivalists, but "creative change" was the touchstone of others. So both impulses were there even in the time Van Ronk is talking about. And this didn't neatly break down into left and right, or any other political distinctions.