My summary, above, is aimed at explicating a real risk to forums, hence the vital need of a moderation policy. Fortunately, at least IME I find BCG is quite different, indeed special forum IMHO.
I think the issues you identify are valid, but it's more to do with the web tools and software search engines to filter and and find earlier Posts & Threads.
I find the existing search tools often struggle to find earlier threads, so I have built up a sizeable database of bookmarks to threads on many topics (!) Bags, safari questions, tripods, exposure etc etc let alone about Nikon products. This works well, but it's obviously parochial.