And in fact, many people do use this information: numerous times someone has said something like, "Since my position is against community consensus I think I will have to modify it," or something along these lines.

Well, certainly not in those terms, but I've seen things along the lines of "EDIT: Am I missing something?" on comments that get downvoted (from a user who isn't used to being downvoted, generally). Those can have a positive effect.