My hot take: glTF adoption is so slow because it does a lot of things people don't need it to do. 

I need the skinned 3D model and the animations. I don't particularly like to put the texture on the 3D file.  

But what i'm sure i don't want to put there are physics objects, lights and totally not cameras. 

I guess it makes sense for importing from blender to maya, but i don't want that appearing in my engine.

I would still be using obj if it was open. 

 @a9012b08 I am confused. Who do you need to adopt it in order to use it? All the engines and tools I use support it just fine. If you're implementing it yourself, you don't have to support all of it. 

 @a9012b08 we wanted to use glTF in our current game, but it has the issues you mention, it's still not worse than FBX, but not much better either... ugh.