All questions get answered but not all of them get "Best" answers. So they are left behind. But wouldn't it be great with a "This answer doesnt fully answer my question" mark. So that other users could answer that question and provide what the asker wants. That would bring the questions better answers.
Maybe asker / Moderator / Editor could give that mark is they see that question.
It could also be something like if 5 or more thinks that the question is good answered or if the answer misses something it will also get better. It could be a kind of flag.