Boats are already made in molds in few pieces. No savings in labor can be expected by switching to carbon/epoxy like there is for airplanes. So the boat just costs WAY more to build in carbon/epoxy. No way around it.

Carbon won't be getting cheaper anytime soon. In fact, the price is expected to rise because the manufacturing process is energy intensive.

Fiberglass has never been competitive in airplne structure because it lacks stiffness. Riveted aluminum is better structurally than fiberglass, though laborious to assemble.

Airplanes are getting more and more carbon/epoxy structure mostly to save labor ($$$) not weight.

Get it?

Jimbo