The other thing is that carbon fibre bikes are largely "plastic" too.
Unfortunately they are also aping the diamond frame, but I think this is because of dinosaur rules from the UCI (someone correct me if I'm wrong).
I have an Australian designed carbon fibre frame from a company called EP-X which is a monocoque, very stiff, and even folds! The chainstay folds under the front of the frame, but not with the wheel on. It even has a small amount of rear suspension.
These bikes were originally available with belt drive, and mine came with a Rohloff hub.
I've attached a photo of my spare frame.