"a reaction against the proliferation of pseudo-American accents which were beginning to dominate the revival".   

I'm all for that!

I gave up the blues (mostly, and those that remain are not really done in the pretence that I am a share-cropper any more) when I did realise that I could not possibly have a proper apprecation of the life experience of the originators. The number of people who can sing convincingly in an idiom that is not theirs is almost as limited as the number of Americans who can pass for English.

I know one and one only surviving white middle-class blues singer who truly sounds the part. Jo-Ann Kelly (of whom I was quite a fan, and was quite a close friend of my late wife, before my involvement) was one. That is not the rule but rather much the exception.