The simple fact is that answers change. Especially in this SE where new content and plot lines are constantly adding knowledge.
So an answer to the Marvel Fantastic Four franchise (to pull a random example out of my ...) may be X today, however a new movie can completely rewrite that. Hence, "correct" answers are "living documents."
The dilemma is, since any given answer's owner's intent can become obsolete, would it not make sense to integrate new (or previously unknown) clarifying information into a "winning" answer?
Of course there is the simple option of posting a completely new answer, however that answer will never get the views like a new question would; will never match the original's vote count, or reputation count. It seems adding an answer to an old question detracts from the quality of the site by placing a negative bias against new information.
How is "The answer to this question has objectively changed" most fairly handled if we can't fundamentally change an owner's intent?