DO NOT TAKE THIS AS A SLAP AT ANYONE!!!!!
The prices you can expect to pay, for the most part, depend on how much of the work is done by the maker himself. Items such as who made the damascus, cut out the parts, ground the blade, heat treatment, ETC all come into play. Ready to go knife parts and services are available from many sources, Knife supply companies, table holders at knife shows, jobbers, etc. The quality of these parts range from "Darn Good" to pure junk. The cost to produce batch lots of blades at a jobbers shop is significantly less than those made one at a time by hand. It's not hard to see that prices can be reduced by farming out part of the knife.
It depends on what your idea of a custom knife is. To some, the out sourcing of any part of the process would keep it from being a custom knife, others wouldn't give a hoot so long as the end product is of good quality.
In the end you the buyer decide what is best for you.
Old Pete