One man's opinion:
I think custom rifles prices are down and continuing to head down. The same seems to be true for most older domestic and imported SxS's. Also Browning A-5's.
I think it is due to demographic changes. The younger shooters (working, good earners) seem more interested in semi-auto black rifles than in traditional walnut stocked bolt actions. The ones I see prefer gas-operated semi-auto and O/U shotguns, rather than SxS's.
Us old fellas (FOWG's) are dying off, and after the funeral the kids sell (or trade) Grandpa's A-5, Model 12, or Ithaca SxS to buy an AR-15 clone, or a Glock.
Interestingly, and counter to the above thesis, prices of older Colt & S&W revolvers are climbing rapidly ???
.. gold40 -- (a Fat Old White Guy)
My kids, grand kid, and hopefully great grand kids are going to inherit the gamut from hammer shotguns and single rifles to the latest in modern arms.
One thing I have noticed, is at about age 35 they develope a greater appreciation for walnut and steel. Or at least my tribe has.