Blake Griffin leave. At that point, I'm not sure they would be competitive enough for Iguodala to want to join them.
Perhaps he may be convinced to go back to Philadelphia where he was once a star player. With Fultz at PG, Simmons at PF, and Embiid at C, adding Iguodala at SF would probably help them become competitive in a hurry. And if he were to sign at a low enough price, they would still have the cap space to go after another big name player.