That is not a very realistic trade at all.
If you want to get technical about it, it is because his value to other teams is higher right now than his value to us, since his value to us is represented by the difference between his value and the value of the "next best option" (which would be Boston, or Gilmore)...while his value to a team like the Eagle is the difference between Booker's value and the value of their "next best option" and since our "next best option" is plausibly better than theirs, the disparity creates the possibility for trade.