I don't think the Sixers have a choice. I think they have to hope Embiid continues to mature and the team gets a little better. I think IF Embiid could play 4 series in a row (22-24 games is a guess) they are close right now.
I also think, in fairness to Embiid (I do think he could be in better shape) that the new age sports medicine of putting a lot of muscle/weight on these guys young does increase their chances of injury. You look at the old big men - Chamberlain, Jabbar, Russel, Lanier, etc..- they put weight on naturally over the years. More weight - same ligaments, bones and tendons - more injuries.
This team is fun to watch! If they can't get it done and are not that close in the next year or two I think they move Simmons.