Well if you have not noticed, there are not very many anime with jazz as their topic. Yes, we do have anime (like Cowboy Bebop, Baccano! and much more) with some instances of jazz within its soundtrack, but it is not the same as having a jazz-themed anime.
There is a great number of musical anime with classical, pop, and rock music as the main focus. Jazz needs its time to shine not just set in the olden times and create the anime in a modern setting. Kids On The Slope is a great representation of a jazz-themed anime, but so far it has been the only one!
Now, there is another musical themed anime, concert band. A concert band is more so about the instrument set up, rather than being a genre. It involves a number of music genres, composed or arranged, for the ensemble; yet, not commonly shown in anime. A more common arrangement of instruments, orchestras, are seen, used, and heard more often than most.
When will jazz and concert bands become the center of attention? Let us embrace all aspects of music! And for you music and anime lovers out there, let us know what you think about having more musical diversity for anime.