Simmons has a lengthy contract, and there are multiple stars in the league on teams in tenuous situations that can demand out once the season has started.
If Morey thinks the Simmons contract can be used to structure a deal for Lillard or Beal or whomever, then he shouldn't come off it for peanuts. He should wait it out and see what happens at the deadline. Sixers will still be in the playoffs without Simmons. (They won't win the East or anything, but they weren't gonna win the East with the current roster anyway.)
And if the big names aren't available, he can still make a scaled-back-expectation deal then. There's always time to make the scaled-back deal. But unlike the Pelicans with AD or the Rockets with Harden, Sixers are in win-now mode over the next 3-4 years. Future draft picks and role players just aren't going to be that enticing (unless it's an absurd amount of assets).