What I think stands out is that the UK bands who made it to the top during the 1960's and 1970's were the ones where the musicians fell in love with southern R & B and actually went to Mississippi, Georgia and Tennesse, sought these guys out and learned from them. It's interesting of course to note that it was the British bands who did this, they achieved global fame and that's when southern blues began to be appreciated in the US - Keef and Ronnie certainly were a part of that as was Page and Plant, they were well ahead of the trend and of the Americans who were for the greater part, very racist at the time. And it was the poor plantation black people who headed North to places such as Detroit, where they clustered and searched for employment and Motown was born, Motown, motor city, the home of R & B and Berry Gordy. Interestingly, ten years after that exedous of migrating black people had arrived in places like Detroit and LA, both cities were in flames in rebellion at the way the white authorities treated them. And today the American cops are still shooting them in disproportionate numbers, but that's another story.