I don't see this happening from either team.
Philly has the #1 pick, they can't afford to give it up from a publicity point of view.
As for the Celtics if Simmons busts, you just set yourself back 5 years.
As the #3 pick, potentially Bender could still be a top talent, also Smart looks like a future 1st team all nba defender. And IT is already a 20+ PPG all-star who can score important points for our team.
Doing this trade today, would probably set us back to a 35-40 win team because I don't believe Simmons can dominate out of the gate. He still needs to learn how to shoot.