Well, it isn't "vinyl" (seating material is polyurethane, which is very different in both feel and durability) and it is only US$1500, but I agree that it must be close to 100% profit. Which is fine if those who really want white are willing to pay for it. Charge what the market will bear!
Seems to me like the white color might have more warranty liability for Tesla than the black if not simply because you can see imperfections and stains more easily. They have this data from MS/MX if it is true.