It's amazing how fragile the record can be. Robert Johnson exists for us primarily because someone recorded and kept a handful of wonderful songs. I've been able to find film of some of the musicians who influenced Chuck Berry on youtube-- T-Bone Walker, for sure; Illinois Jaquet; Louis Jordan. But I haven't had much success finding Elmore James. The best you get on youtube seems to be a still photo or film of a spinning disk.
Luckily Elmore James' music was recorded more often than Johnson's-- but if my (meager) search skills are evidence, no one seems to have made a movie of him or put him on television. I guess it was a question of crossover appeal-- something he didn't have until he was gone. Muddy Waters lived long enough to be "discovered" by the white majority of music fans in the 60s. Same for Lightning Hopkins, and Mississippi John Hurt, and a host of others. jaquet and Louis Jordan made it into the movies. But Robert Johnson and Elmore James were gone before the camera crews arrived.
Of course, there's another way to look at it. Elmore James took Johnson's music north and plugged it in. Chuck Berry saw and heard James and used the same riffs for at least a dozen songs.
So the record may be fragile-- but the music is strong, and keeps going, delivering us from the days of old, and delivering us ancient wisdom and magic at the same time.
Here's Chuck, channeling Johnson and James, with the song "Bio." Hail! Hail!