In this question, the accepted answer has lots of down votes. Should the community revise the accepted answer?
There may be other questions like the one I've linked to, that's just an example.
The person who asked the question chose that as the answer that worked for them, which is their right. The community gets to decide whether that's the "best" answer by voting, which they've done. The answer the community voted as most useful is right underneath the answer that the person who asked the question thought was most useful (provided you've not done anything funny with the way you sort answers), so it's hardly difficult to find.
Also, note the comment by the person who asked the question where someone queried why he'd accepted the answer he did:
No need to be concerned. My final solution went ahead with the enterprise library for a few reasons, firstly we were using a few other features of the library, secondly I liked the implementation and thirdly it was powerful enough for our needs.
In other words, the answer met his needs, which is sort of the point of the site.
What's the problem?
I don't think they should. The OP clearly explained why he marked it as accepted. From the FAQ
When you have decided which answer is the most helpful to you, mark it as the accepted answer by clicking on the check box outline to the left of the answer. This lets other people know that you have received a good answer to your question.
In other words the OP found that answer the most helpful as that was what he/she used.
The community already has a method of indicating what they think the accepted answer should be, upvotes. I don't think setting a precedent of changing accepted answers would be a good idea.
I'm not sure how you would edit this post. People didn't like the product this answer recommended. You certainly wouldn't edit the answer to recommend something different.