But it sounds like they want to seem like they're not trading him:
After everyone in Philadelphia vented their spleen, this is where they have to end up, because Simmons is extremely talented and they can't possibly hope to recoup his ability in a similarly-talented box of another shape.
He's a very tall prime Jason Kidd, which means he'd be one of the best players in the league in any other era, but in this era, inability to shoot at all is a fatal flaw. He can't tie together all his value without some semblance of a shot. Other teams know that, so they're not going to trade an effective superstar for a fatally-flawed one. Philadelphia's only hope of reaping his value is getting him comfortable enough with shooting that he
A. shoots when he's left open and
B. hits enough of them that the outcome of the average possession in which he shoots is positive (which means the three-point mark he needs to be above is probably around 33%).
He may never get there, but that's at least not an impossible standard. Kidd himself showed that improved shooting isn't impossible. If Simmons can hit enough three-pointers that
not defending him isn't a viable strategy, suddenly everything else he does at a very high level catapults him into a potential top-ten player. He'd basically become the new Scottie Pippen.
I mean, the other option for Philadelphia is to trade Embiid for value, but that ain't happening. You can build your offense around one high-minutes non-shooter but not two.