Well said, Fortunato. I didn't want to neglect the content by focusing on the form; both are essential elements.Steve, I absolutely agree that bluegrass is closely connected to the blues. People tend to recognize that jazz has blues roots, and that rock'n'roll has blues roots, but I think a lot of folks don't recognize the influence the blues has had on other musics -- including bluegrass, and really on a lot of country music.
One thing that's great about all the cross-pollenation that has gone on between "white" musics and "black" musics over the years is that it has fostered respect and understanding among the people making the music -- who otherwise might not have had a way to relate to one another. And, as the music has been disseminated from musicians to audiences, so has some of the respect and understanding. The process isn't complete, or course, but I think the blending of musical forms has been a tremendous force for social good (on top of the intrinsic value of the music itself, of course).