I think I learned matchbox blues from Hamish Imlach, or it could have been around the same time I heard the recordings of rambling jack Eliot. Also Mike Cooper of Reading folk club did a couple of Blind lemons songs - this was about 1964-5.

I think I understood the songs in those forms - but when I heard the original recording - I realised I was a long way out of my depth. I will listen again. To be honest I found robert Johnson quite a hard listen intially. I know some people say they were blown away from the word go - but I wasn't.

as you say he was much more commercially successful then RJ - so I suppose he can't be THAT inaccessible.