According to Joshua Redman, what people have called jazz over the years has changed so much. I definitely don't define jazz as a style or set of styles, because the stylistic components of it will always be changing. I don't know whether you agree Joe (Joe Lovano) but there are certain things like swing, that are crucial components of jazz and almost anything I would call jazz has something of that. The improvisational attitude, bringing your life experienceto the music, that is the key thing, not the stylistic elements.
What Joshua said sounds pretty good to me, but I'm not in the defining business, I'm a listener, and when I listen to current music called jazz, it just don't cut it. No longer am I going to listen and try to make sense out of it, I don't have that much time. While there are exceptions to that, they are too few and far in between for me to bother.
Recently, almost every day, someone is posting old jazz that's new to me, and it sounds like my kind of music; consequently, I am not going to waste another minute or peso investing in "new jazz", case closed.