I used to follow these free 3D engines, waiting for the magic one to come along with the "make game" button enabled. 

But IIRC many of them weren't actually game engines, rather just tech demos of someone's rasterizer project.  And the ones that you could actually make agame in had strings attached...

The ones I remember most impressing me were CosmoCreator and Beyond Virtual.  I'm sure none of what was available then can compare to what's availbale now in Unity or UE4.

I do miss some of the more promising 3d stuff of about a decade or so ago...  Remember Merlin3d that was designed around the space navigator?  And whatever happened to Anim8or...  Don't even get me started on TrueSpace's demise...

Communities don't usually just disappear, they tend to migrate.  If less people are using Poser, and I don't know that this is even true, they've probably moved to iClone, Daz, or a more full featured program such as Carrara or blender.  I strongly doubt that the idea of animating 3D characters appeals to fewer people than it did 10 years ago.