You can procedurally generate textures, sounds and geometry
Does any game do that today? I’m not aware of any. ??
Another thing that compounds on the lack of planetary variation
That’s the same problem again, you need hard drive space for all that 3D variation.
As far as I know all the 3D stuff is what takes up the most space on the hard drive, and that stuff is never procedurally created. /shrug Maybe someday with AI??