Thanks for the heads-up about the program. Hasn't started here on the west coast yet.
Our bluegrass experts could tell you a little bit more on this -- I've been away from the music for quite a few years -- but I don't think Monroe himself would have argued with the common knowledge that, with the inclusion of Flatt & Scruggs to hs band, the bluegrass movement began. Standard bluegrass bands have banjos, so the Scruggs three-fingered banjo playing was, I'm sure, a key element. I have read Monroe had been developing the high tenor singing and driving mandolin playing prior to that, but the band was still thought of (and thought of itself) as a string band.
Paul Kingsbury is an author of several well-known country histories, and is a director at the Country Music Foundation and an editor at the foundation's Journal of Country Music. It will be interesting to see what he says, since he's currently at the core of that huge controversy at the Journal -- where 30-year editors and historians were summarily fired and a new direction announced (this must have been discussed here -- I'm new here). Anyway, the "new direction" amounts to a total "Garth-ization" of the respected journal, and if there are "villains," Kingsbury would have to be one.