This brings up a great point. Great jazz players are horrible marketers. Oddly enough, I think some of their "practice" time could be better put to use spreading the word or pounding the pavement.
It is niche music, there is no doubt about it. The jazz festival circuit seems to be doing just fine, albeit, most of the popular festivals are outside of the US. Heck, most of the really good older jazz musicians moved to Europe 30 years ago, anyways.