While I am not in the "forums are dead camp" per se, I just yesterday searched for forums on vintage/retro computers and found some that didn't look very active. Granted, they had far to many subfora, so maybe I just missed the active corners, but there was very much a "last post 3 months ago" vibe, including threads about the question if the scene was dying.

Though really, the main problem with good forums is actually finding them in the first place. If no one points you at one, google might just be no help at all. Of course, discourse invitations seem even more obscure these days, so its probably just the way things are now?