Well, regarding Answerhub, by now 90% of questions are either regarding things already covered elsewhere, or duplicates of existing questions or just obvious misuse of a feature. Bug Report section is not an exception. I don’t think that the section gets less attention than it deserves, though there were occasional cases, where efforts to review the bug report were incomparably lower, than efforts, invested into reporting one, but overall, I don’t see major issues with that.
Not sure if it is viable, even if a sole person is dedicated full time to this. There gotta be some filter to make sure only the relevant posts are reviewed. I’d say here that one thing, that is not used properly on answerhub, is voting system. Sadly, number of votes on the question are not indicative of relevance and quality of a bug report.
For some reason, I don’t have any doubts, that overriding majority of threads are looked at, just no responses are given. I’d guess a simple logic, that no response is better than wrong response applies.
I also think that decline of post numbers shares same roots, as reduction of all forum users activity: forum update.