Right on, Merle. Flatpicking is hard! Put a piece of plastic between your fingertips and see how long you can wiggle you wrist back and forth before it starts to hurt. With their big open chords and modal rubs, bluegrass guitarists create a perfect synthesis of Celtic, American and African traditions which, essentially, their music is. Bluegrass legend Larry Sparks gets some remarkably bluesy sounds from his acoustic--sounds almost as if he misfrets or plays out of rhythm. Unique. Tony Rice is THE MAN in this genre. And rhythm guitar, while it looks deceptively easy, is no cinch. Lester Flatt plays in a style that today's superpickers, even by slowing down the old recordings to half-speed, can not seem to duplicate. I'm afraid his style is lost forever. And Del McCourey is a mountain.
That said, have you noticed that even some feted guitarists (and conductors) are unable to play behind singers? Martin Simpson most definitely can. What taste and what an ear. What an ability to bring out the best in another performer.