The OP brings up a good point, but I doubt the AT forums are going anywhere soon. Prior to joining the forums I was a lurker for a good while, and it seems like the amount of activity and the content really hasn't changed too much. And something tells me Anand isn't worried about the cost of the bandwidth needed to run the forums.
That said, I used to post a ton over a patent law forum. i gave it up after a couple thousand posts though. I was getting nothing but grief out of it, even though I found it fun to answer questions about my profession. If the AT forums went away I imagine I would feel much the same way as I did when I left that other forum. A bit sad . . . but only until I found somewhere else to post.
I would miss quite a few folks on this board though. Rudeguy, Rubycon, Sjwaste, Dirigible, Corporate Thug, Ned, Drpizza etc. . . I've enjoyed a lot of their posts, even if we disagree from time to time.