This has frequently been true of the General Discussion forum, but the Critic's Lounge, Competitions and Activities, and technical forums seem to be staying on-topic fairly well. Since the general forum is basically the cesspool of AGS interaction, it's hardly productive to expect anything more from it.
I will agree, however, that there are many less interesting threads that provoke discussion, debate, or introductions to new subject matter. The number of "I like X, do you?" and "Name your favorite poodle breed" discussions has sky-rocketed in the last several months. Perhaps people got burnt out by all the religious, morality, and political discussions that took over the General Discussion area for awhile. For my part, if a thread seems pointless or uninteresting, I don't reply, I just wait for it to sink into obscurity. It's taking far too damned long for some of them though.