It's interesting that Kelley wants to freshen up the 60s/70s "mack-daddy" image of Miles, and doesn't really deal with his class background at all.
If you read the Quincy Troupe autobiography, Miles' father was a dentist, and in addition, had a large hog farm near East St. Louis. (That was where Miles went to kick his H habit.) Miles Davis was the only middle-class black up until that time to make a (successful) career of playing jazz. I can't think of another, not even Fletcher Henderson.
You also learn that, of course, Miles terrorized his wives and lovers, but the only ones Miles ever dumped were Lynn Mabry and his first wife, I think. Both were of a more working-class background than his other romances, and more working-class than he.
My takeaway was that Miles' anger at whites was largely brought on by his being their social equal. Racial discrimination for Miles went beyond skin color to a class demotion as well.
As for his wives, the middle class ones like Frances Taylor were forced to quit their jobs, I think because Miles perceived "being the wife of Miles Davis" was higher status than dancing a minor role in the B'way production of "West Side Story." The independence they had achieved was both an attraction and a liability for Miles. Also part of why he could never let go of them. But he ditched working-class Lynn Mabry because she was too "funk mob" for him, and also likely could beat the crap out of him when he got violent.
Best, Charles