I bet they cost under $200 to make. They are just molded plastic and stamped sheet aluminum with a basic quick leather wrap and a few feet of wire. The magnet is probably the most expensive part and I bet it cost them around $50 or less and that is just because it is custom made for them in low quantity. They even leverage the process with their other headphones like the T5p which use mostly everything the same. Different voice coil of course.
Guessing $50 for the motors, $25 for the diaphragms and windings, $25 for the leather, $25 for the stamped aluminum and cups, $25 for the metal box, $10 for the cable assembly and the rest in assembly and testing..