Work in Progress: on the first page, 14 new topics started this month. Out of 30. Just under half. One of those threads in that section have been going since 2009. Most of the topics started this month have less than five posts to them. I'd say it seems... fairly average for a forum. Not massively busy, but not indicative of it dying, either.
3D Editable Examples: certainly far less traffic here, but one or two thread names stand out (Non-ortho cam, Terrain generation, terrain by heightmap). I don't see any threads started this month, nor do any of the threads seem to have been posted in this month. The 3D Game Techniques forum proper does seem considerably busier, though.
I wouldn't really say it's dying. Not massively high volume, certainly. The biggest issue I have with the GMC is the separation of the WIP forums and sometimes missing out sections for the platforms they support. I'd say its biggest concern right now should be its slightly hap-hazard design.
You may want to ease off on the hate-on for YYG/GM, too. They aren't worth it.