If however you strive to own something special and uncommon made in an exceptional way then $400 can just be a starting point.
Yes and no. In my opinion only 2 VALID factors decide a knife's realistic value. Production cost and scarcity. Let me give you an example:
Boker has a knife called The Tirpitz. It's a knife that has a damast blade that was forged from a chunk of steel that was recovered from the WWII German battleship Tirpitz, that was bombed and sank off the coast of Norway. The scarcity of that material combined with the obvious cost of securing it, in my opinion warrants it's well over $400 price tag even though it's not a fully manually produced knife.
On the flipside of that coin, I fail to see why, for example, a Chinese produced small slip joint folder coming off a mostly automated belt but sold by a US company has to cost $350?

