Boards are made in a mold. Mold cost is easily $10k per half, probably more. As the boards get longer and/or curved, you need more materials to get the strength up. It also takes longer to build the board. I'd estimate $300 in materials and $900 in labor to build a curved F20c board. The rest of the money is covering R&D, mold cost, and warranty.
And you need four mold halves where-as a port and starboard straight boards can be made from the same two mold halves.
