It is what it feels like, but it’s not really 100% this way (yet). It is a bad self-reinforcing cognitive bias: we think “forums are dead, that’s why we stick to the sitename” instead of actually finding dozens of still alive forums and going there, in turn sitename gets more populated while forums feel more dead. But there are still plenty alive. Also, there are relatively new kinds of forums which sometimes work very well for their niche, like Discourse communities for example.