OK, but he could have lost one of those fights too...
The only high level HWs JDS hasn't fought yet are Overeem and Brock. and presumably their timeline would've been the same regardless of Cain's injury - Brock goes through surgery while Overeem is still fighting for Strikeforce, they fight a title eliminator that after which Brock retires and Overeem is suspended.
It's not like the UFC could've wished a different contender into existence. these are the HWs the UFC has, and JDS has gone through all but Overeem like a buzzsaw. It's not like any of those fights were close, even the two decisions were one-sided demolitions.