Probably something relating to import/export fees and outsourcing costs combined with still needing to make a profit. When a company goes outside of China and Taiwan to have something made overseas, I imagine the overall price goes up - even if the materials and production facilities are already geared towards mass production.
One would think, but if that were the case, I'd think you'd see a general bump in prices across the board for the Japanese made Spydercos. However, the D-Fly, Delica and Endura are all great values with either FRN or stainless handles. As are the Salt series knives, and the Police. Heck, an Endura with Ti scales and Damascus blade is only $200, which isn't cheap but considering the materials is certainly more than reasonable.
However, as soon as you get into G10 scales you get things like the
Roc Cleaver- VG10 - $175
Firefly- VG10- $175
Q ball bearing, VG10, $178
D'allara- S30V- $211
Temperance 3, S30V $211
Even a head to head comparison of the same models with the same steels but different handle materials:
FRN D-fly VG10-$60
G10 D-fly VG10- $107
FRN stretch (ZDP-189) $136
G10 Stretch (ZDP-189) $234
In the head to head I can see where some of the additional cost comes from a more expensive material and labor involved with G10. I really do get that, so I'm even willing to toss those as examples (although $100 extra for G10 scales on the stretch does seem a bit extreme on its face). However looking at the first example, when you've got VG10 and G10 scales going for $175, and S30v with G10 going for over $200, I just can't imagine not looking at something within their own product line or at another company's lineup that offers better bang for the buck.
When the FRN examples are so reasonable, and the G10 examples are not competitive with other knives in the same price class even comparing to their own product line, it seems like it's the G10 that actually makes the difference... why? I don't know.