U mean that guy running away from competing after Doz entered the scene, knowing that not even the Mr. Olympia bonus could get him another gift next year?
There was nothing more for Haney to do. He competed for one reason: To break Arnold Schwarzenegger's record. And, he retired at the top of the heap, not riddled with injuries or a shadow (no pun intended) of his former self.
BTW - Haney was not undefeated, per this poster's title thread (he lost to Bannout in 1983).
Why didn't Yates compete in 1990, if he were so scary and Haney was so supposedly terrified of him?
Yates in 1992 basically looked the same as 1991, which was pretty great in its own right. Basically, he was a white Lee Haney (with a slightly wider waist) and that's why he won.
At the same size/bodyweight (as they were in 1991), Haney beats Yates due to his smaller waist and better proportions.