I think a lot of people are confused by Simmons because of his handle and his passing. He can do those things like a guard, right? So he should be able to shoot free throws like (at least) a center. He can't and he probably never will. But maybe he's still pretty useful.
Imagine Ben Wallace with passing and a handle instead of elite rebounding, and suddenly Ben Simmons looks pretty good. Unless, of course, you started him next to Embiid.
Simmons is paid like a franchise guy you build a team around, but they never really built a team around him.
Wherever he winds up, the team that acquires him will go all in with eyes wide open, and will structure everything to make him work. I hope he comes here.