It really depends on the library/engine you are using (if you're using one!) OGRE3D integrates well with several packages, Unity has a builtin GUI system that is stupendously inefficient, and the list goes on...
Fortunately, you don't really need to reinvent Qt or CSS to get the job done. A font system and a few hand-coded controls usually suffice.
I think the bigger problem is in sound synthesis and processing. This arena still remains mostly confined to reverb algorithms, crossfaded tracks, and pre-recorded samples, yet the depth of the subject goes about as far as graphics does. So we're really missing out in terms of applying technology to creativity here.
You trade some flexibility and input latency for a simple imperative structure that is easy to implement.