Just a FYI, Carbon has lots of extra cost items.
Carbon frames require polished molds. You do not just pull a mold from a CNC machine and use it. It needs finishing. A mold can only have so many 'pulls' or parts made from it after which time it will need work to correct imperfections or be replaced.
Having worked with carbon and kevlar for R/c plane building, it requires a skilled hand and is partly an art. It is rather challenging to hit a target weight reliably.
If they are using prepreg, the epoxy is already in the fabric. They could be using infusion where they inject the resin after putting the dry fabric into a mold. Both methods will produce a rather repeatable weight. If they are hand applying to dry fabric, it takes skill to recognize when enough has been applied and when it is too wet. A part that is too dry will fail and cannot be sold. a too wet part will weigh too much and the extra epoxy will do nothing to improve strength.
Then you need ovens to heat cure the epoxy. Most production parts in carbon use a heat sensitive epoxy to keep it workable at room temp and to result in a stronger bond by using a post curing temps. It also can take hours in the oven to fully cure and until that i done, nothing else can be put in. The cost to operate and the time limits the number that can be made in a single day.
Also for each part being made, you need a mold for. Those molds are not cheap to have made and this too needs to be amortized across all parts made.
Epoxy is one of those chemicals that everyone eventually becomes allergic to. I am sure they are using chemical masks and /or respirators but exposure will eventually turn to allergy and I wonder if this will limit their lifespan in the job.
With metal, I wonder if the welding frames need replacement as often or if at all. I have no experience with metal.
I would think metalworking can be done more assembly line and only the time to cut weld and treat, etc needs to be worked out and each step , I would think, takes less time so more parts can be made per day.
Another issue is that the carbon tow that is used to make the woven fabric is only manufactured in a rather limited number of locations. Some sizes of tow are hard to come by. In any case, carbon cloth has jumped in price over the last 10 years due to the demand by aerospace ( Boeing and Airbus ) and many other markets.
IMHO