Interesting post, links included, on be.jazz concerning the apparent shortage of a younger black audience for avant garde/modern/free jazz music. Reminds me of an article in the Village Voice a few years back about Black-conscious Hip-Hop's mostly white audience.
Though I believe greatness in music transcends color/ethnicity/sex/whatever, no doubt the experience of being part any group will most likely influence the music. I also understand the need/urge to communicate that experience with someone who shares it (as opposed to e.g. telling/making people understand). Hence, if there were to be a shortage of black American voices in jazz in the future - regardless of which experience they chose to express - it would be a crying shame.