Anyway, H, go get a good selection of Chess recordings from the 50s/60s and marvel at how almost all British rock from the 60s arises from that seminal Chicago label. Maybe your response to it will be able to inform us of why most white rock fans in general don't buy black blues.
I find it amusing that you still seem to be under the impression that just because I don't have an encyclopaedic knowledge of early blues, Garth, I don't know what it's like. It's like the fact that you only need to have seen two or three impressionist paintings to get what impressionism is about - it's a relevant genre of painting which was a huge stepping stone towards modernism, but I don't need to go and study every impressionist painting to get where Monet and his posse were coming from.
I don't own some Chess box set is because, quite frankly, the form bores the pants of me when there's so much else going on, on the planet which is musically more interesting. One or two budget comps is all you need to get the point. It offers no surprises. I know it's the done thing to hold every scratched up old tape or ten-inch as some kind of glorious talisman and template for every great record that has appeared since, but I just don't buy it.
But having said that, of course all those old black dude records from Chicago and Mississippi are a thousand times better than what any white dude has done since, and I can confidently state that I don't own any diluted white-boy blues records of the variety being discussed here either - never have.
As for why white rock fans not buying black blues - I actually think they do these days - otherwise why is there still a corner of most HMV/Virgin megastores devoted to the genre? I'm sure it's a lot rarer to see a black guy picking up a Chess box set and lovely taking it to the counter as if it contained the very meaning of life!