Hurley has said that he one day wants to coach at the highest level and considering his competitive spirit, I fully believe that one day he will. He will however be very deliberate as to where and when he makes his move to the NBA.
Look at where he grew up, where he played college ball and where he has worked since. I believe that there are four, maybe five (Boston, NY, Brooklyn, Philly, maybe DC) NBA jobs that he would consider. I also believe that he won't even think about leaving here until he reaches the point where he feels he's accomplished all he can here (my guess is a minimum of two more titles) and he won't take an NBA job that is set up to fail.
We will be (happily) stuck with him for a while and when he goes we should be able to find a replacement. Maybe by then Kimani or Luke will have cut his teeth as a head coach elsewhere and be ready to return to the mother ship.