GUEST Hootenanny is surely absolutely right.If you want influential Native Americans, try Charlie Patton, the legendary blues singer who I belive had very little black ancestry at all. Wasn't he a Cherokee? As was Leadbelly, in large part, or so they say.
But in terms of cultural influence, progammes like these are surely
right to ignore Native American music, not to mention a lot of European immigrant stuff. The "American folk" that was dominant around the rise of the "folk scene" in the 60's was what the documentaries are about. And this music can be accounted for pretty much by a mix of British/Irish and black African sources. With a dollop of Spanish and French for melodic content.