Hadn't heard that.
I love(d) the guy and his music. Granted, he may be the only blues musician many people can name, and if he is the only one you can name, you're probably not a blues aficionado, But, for many, he was an introduction to the blues, that led to further finds, and greater appreciation.
The fact that he was so well respected by other musicians makes me think the theory you mention is flawed. Blues musicians, rock and rollers, and fellow guitarists all seem to have had lot of respect for the guy as a person, and a musician/guitarist.