We have highly popular question, on extremely popular topic that has an outdated answers (most from 2010, newest ones from 2015): How to choose the number of hidden layers and nodes in a feedforward neural network? The most upvoted answers suggests to choose single hidden layer, while the recent achievements in deep learning show something opposite: the best results are achieved by networks with multiple hidden layers. Moreover, for some problems like image recognition, simple dense networks with single hidden layer are very far from state of the art. Since I'm not an expert in deep learning, I don't feel that I could give a detailed answer on that. On another hand, nobody did recently give an update. I myself offered a bounty for the update answer, but there was no response. What should we do in such cases? I guess this that we don't want to be a repository of outdated knowledge...
While the canonical "StackExchange/StackOverflow" approach seems to be to allow downvotes, edits and new answers and hope the new good ones eventually float to the top, I think that in practice the best thing to do is make a new question (if possible, worded to be in as canonical form as possible), and enure it gets at least one decent answer. Then close the old one as a duplicate of the new one, adding a note that the answers there are now outdated and better answers are at the new one.
This should get to a desirable outcome faster.
Edit: I agree with amoeba that the standard approach should still be used if there's a reasonable chance of that working.
In this particular case, I would first talk to the most active and respected users in the neural-networks tag (see the list of top users and the list of those who've been awarded tag badges). Of course not everybody there is still very active. I noticed that @DeltaIV, @Sycorax, and @JanKukacka have been posting good answers & comments in the NN tag lately, but I am not following this tag very closely.
Perhaps you could identify several such people and ping them to join this Meta discussion or a discussion in chat. If they agree that all current answers are suboptimal, encourage them to write a good (authoritative and comprehensive) answer. I can promise to put a large bounty on that thread once such an answer appears. Hopefully this would attract some upvotes too. Then we can reach out to @RobHyndman and encourage him to change the accepted answer. Profit.