You know how the Internet made fun of Stockton Rush for using carbon fiber in a sub, which is a compression structure? Similar thing going on here. Carbon fiber is a great material for tensile strength and lightweight. It can be used in compression structures, but it needs more careful engineering to pull it off. The benefits do not always outweigh the costs.

As a more general issue, if a car the size of a Geo Metro or smaller can’t be safe on roads, then motorcycles and bikes can’t be, either.