76ers: Tristin Thompson, Marcus Smart, Payton Prichard, 2 future 1st round picks (protected)
Celtics: Ben Simmons
If I were the Sixers, I'd find your proposal borderline offensive.
You guys massively underrate Simmons. Just because he's a terrible fit alongside Embiid, it doesn't necessarily mean he's a choker. Both Simmons and Embiid are at their best when playing close to the basket. Imagine Simmons playing off the ball in the half court, setting picks on the perimeter and then rolling hard to the basket. He'd transform into a dominant 2-way player. I mean, is Simmons all that different from Bam? Neither of them stretches the floor, yet nobody is complaining about Bam's shooting. Simmons is a more versatile/switchable defender. Bam is a better rim protector. Other than that, their games are very similar.
If we somehow put Simmons next to the Jays, I'd consider us the #1 favorites to come out of the East next season. Not to mention, he fits our time window. Simmons would make the C's a legit contending team for years to come. It goes without saying that I'd do the proposed trade in a heartbeat. In fact, I'd be willing to offer way more than that. For instance:
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The thing is, Simmons and Embiid aren't a terrible fit when the roster makes sense around them. Aside from the Jazz (and some other team - maybe the Clippers), the Simmons/Embiid duo had the highest Net Rating in the sport of duos with a decent amount of minutes. Simmons has been grossly mismanaged because all of his coaches have tried to make him the #2 option on offense. He isn't that. He is a 4th or 5th option, but the Sixers have a guy in Harris who shouldn't be a 2nd option and the rest of the team are off the ball shooters (which would be fine if Harris was better). The Sixers problem is much more that Harris just isn't good enough to be the #2 with Embiid or the #1 when Embiid isn't on the floor. They've certainly tried, I mean when they upgraded to Butler they were inches away from the ECF (and possible title) but Butler and Simmons weren't a good fit and Butler had different ideas anyway.
The reality is, a team needs to treat Simmons like he is offensively an interior based PF. Build a team around that concept and I think he could excel. He is never going to be a shooter, but he can dominate players inside with his quickness, passing, etc. That is hard to do with Embiid, but I think it could be done. Doc Rivers is quite simply a terrible coach though and I'm not sure Brett Brown was any better. It doesn't help that an inexperienced guy like Elton Brand was making decisions on his own there for awhile either. Morey at least has shown some solid ability to team guild around unique players, but I'm not sure that fits.
As for the trade proposed in this thread, the Celtics would do that in a heartbeat. It would be a fantastic trade for Boston, which is why Philly would never do it. Thompson is basically worthless to the Sixers, a couple of protected 1st's (so later picks) have very little value, and Smart quite simply is no where near the player Simmons is, plus is expiring. Philly would need at least 1 of the young players if not more to even consider that trade (like if R. Williams and Langford were included they wouldn't at least hang up the phone laughing), but frankly I don't think there is a viable trade as I would expect the Sixers to be able to do a lot better on the open market. Portland, for instance, might be willing to do a trade centered around McCollum.