The solution to this is to get the original question asker to consider changing the accepted answer. You can leave a comment on their question if it's many years old to bring it to their attention.
Yeah, success definitely varies if the person is no longer active and doesn't respond to the email notification. I've had mixed results with it in the case where the asker (new to SO) didn't realize upvoting answer(s) and accepting an answer are different things.
If it's a really popular question I think making it a community wiki is an alternative.
