One more observation: We have no way of knowing how Robert Johnson, or anyone else among his contemporaries, actually sounded in the context of a loud juke joint or a busy outdoor streetcorner, nor how he approached playing in these most common venues for blues players in his time and place.

We only know how RJ sounded when given the opportunity to play into a microphone, on a borrowed guitar presumably of higher quality than his own, in a hushed San Antonio hotel room. It would be surprising if he did not play with a bit more "delicacy," and perhaps include a few more embellishments, than would have been part of his "normal" nightlife performances.