First off I wholly reject the concept that Ben Simmons is broken/cooked/not good whatever. Simmons is easily a top 3-5 defensive player in the league, has not missed a game to injury since the tanking redshirt rookie season, and has spent his whole career playing with a player who has the box stacked against him every game. I may be naive, but I believe that Simmons will more likely than not excel in a new environment.
I'm not saying that it's unfair to criticize how his career has gone thus far but I am saying that it would be negligent for a GM to write him off from the struggles that he's had in Philly. Ben Simmons would be an excellent addition to most teams in the league and in our case would work particularly well with Tatum given how complimentary their games would be.
https://www.youtube.com/watch?v=KQk33-7dm9g&ab_channel=Philadelphia76ers
Tatum and Simmons in the 2020 All Star Game
All of that said, I would not do a strait Jaylen Brown for Ben Simmons swap.
Jaylen is currently on a tier of young players that Ben Simmons was on at one point but has since fallen off. The Celtics trading Jaylen for Simmons is nearly all risk on Boston's end and the best Philly could do outside of James Harden. If the FO does decide to move Jaylen there are probably 5 offers they know of right now than would be safer than trading for Ben Simmons.
Now with that said, if Simmons can exercise his demons he still might be the best player we would pair with Tatum in a Jaylen Brown split. A fully developed Ben Simmons is a better fit with Tatum than Beal, Lillard, Porzingis, Siakam, DeAaron Fox, etc. The question is can he get there?
So I voted 'Maybe, if the package included…'. Maybe there is a deal out there enticing enough to consider, be it draft capital, Tyrese Maxey going to Boston or another team, and/or Matisse Thybulle. Something to offset the risk of breaking up the best young core since Durant/Westbrook/Harden, but not so much that Morey would never even consider it.