My best friends brother played piano, they had a baby grand, and he went to Juilliard. The next door neighbor would come over and listen to him play and practice. After watching for a few minutes, the neighbor could play anything he played. While he grew up to teach music and never record, the neighbor became an entertainer who could jam, he could set the house on fire; I watched him do it many a night.
I don't have a clue as to what it takes to be a "jazz musician". While I had a friend who was a professional "jazz musician" live with me for an entire summer, who never practiced, (since I didn't have an organ or piano, he couldn't even if he wanted to). We never talked music (if Einstein was your friend, I doubt you would be discussing his "Theory of Relativity", especially if you didn't know squat about it) The mesmerized look on my face every time I watched him play, certainly told him what I thought about his music; there was certainly no need to discuss that. We talked about his life as a professional jazz musician, he never got tired of talking about it, and I never got tired of listening to him talk about it.
Although I have every record he ever made, the music he played that summer was far advanced from those records; that pains me because he died before any of that music was recorded; now it's just a memory I can't prove. These thoughts came to me after looking and listening to the "Lennie Tristano" interview; that's a very important in depth interview about being a "jazz musician". Lennie said, "You could make your fingers reproduce your deepest feelings", and he added "All you do is hear music in your head and reproduce it". [11-07-14]
Some got it, and some no got it.
Shiela Jordan studied with Lennie, and she's a great jazz musician, here she is;
http://www.youtube.com/watch?v=ZZHteISQ-bw http://www.youtube.com/watch?v=6r8XF9YkyeMEnjoy the music.