In my opinion, there is a moral obligation on those asking questions to do something with the answers: Either accept one, or to explain why none of the answers is satisfactory. I do not see this stated anywhere. Should that be included in etiquette rules, and perhaps even encouraged by incentives?
Because this is a publicly viewed forum, in my opinion, there is no moral obligation of the original poster to do anything with the question after it is presented. (Private forums are a different matter.) There are social niceties such as editing to improve the question, responding to answers, and even accepting an answer, but most if not all of these can be done by the community or the forum moderator(s). I would like (for increased understanding of motivation) to engage with the questioner, but not obligate them to such an engagement.
As noted, there are some incentives for such engagement, and for each forum, the community there might want to encourage more (or less) engagement. I still do not see obligating the questioner to do more than provide the raw source material.
Gerhard "It Has To Start Somewhere" Paseman, 2019.06.24.
If there is no way to make an user accept a good reply to one his/her questions, wouldn't it be nice to make up to the author of the unaccepted answer by awarding him/her a new type of badge? Obviously, there would be a restriction from below on the number of upvotes that such an answer ought to receive in order for its composer to become an awardee of the badge.