From another musicologist...
The history of black music since the Civil War has been cycle after cycle after cycle of black musicians creating a new musical style, which eventually gets picked up by non-blacks, which makes the style useless to black performers who want something unique to them, which causes a switch to a new style.
First minstrel, then ragtime, then dixieland, then blues, then bebop, then rock-n-roll, then soul, then rap, then hiphop. What’s coming next? Hu noz.