Good heavens. What sort of lunacy is this?
(1) The sport in which there is seemingly the largest pool of qualified African-American head coaches is men's basketball. That job hasn't opened in 27 years, and isn't likely to open soon.
(2) There are arguably only three African-American head coaches in women's basketball with the quality experience to be capable of taking over a high-profile and demanding position such as Duke's. One resigned from her last position under a cloud of suspicion; if she did what she is alleged to have done, that behavior disqualifies her. The other two leveraged the mere availability of the Duke position into significant contract extensions and/or salary increases, and showed no interest in the Duke position as a result. Duke has, in reality, been part of the solution in women's basketball, as two African-American former Duke assistants have gained high-profile head coaching positions.
(3) African-Americans with head coaching experience in football at the BCS-conference level can do a lot better than Duke, as can the small number of African-American co-ordinators who are arguably ready to take the next step.
(4) The pool of African-Americans qualified to coach non-revenue sports at the level at which Duke competes is infinitesimally small. I challenge you to name one African-American who would be qualified to take over, say, the Duke field hockey program is Coach Bozman were to be kidnapped by aliens tomorrow.
It's called an imbalance of supply and demand. It will take at least a generation to change. Racism has not a thing to do with it, and your suggestion to the contrary is scurrilous and indefensible. Get a clue, willya?