Karpiel Armegedon all decked out reaches around 10,000$ at its peak. Considering there are a couple of companies making dh frames in the 3500$ range 6000$ is pretty cheap for a complete bike
You also have BMW who has a starter frame at 3500$ Figure to add a 1500$-2000$ fork and things get nutty
. With the new saint lineup I have no doubts the freeride/dh custom market is going to increase in price this year