It's also an extraordinarily difficult instrument to make. There are well over 2 dozen adjusting screws, and the mechanism is almost like a Chinese jigsaw puzzle in the way that the rods and levers fit over, under, and next to each other on the oboe body. The bore is incredibly small, and requires enormous precision in drilling; it's a stressful thing to make an oboe, and a large part of it must be done by hand.
So, combine that with the demand (or lack thereof), and you've got yourself one expensive little creature!