I'm not sure how many rounds my Model 1873 has had through it, but I am very sure if I were to sell it, my asking price would honorably be well over 10 times what it originally cost new, because of things like age, condition, significance.
As far as comparing the scenario to new guns, my asking price could be considered high because they don't make that model anymore (not counting replicas), and to get another one would be much tougher than walking down to your LGS and picking one out.
Thats just how the market for certain guns works, especially antiques or historical/collectable guns. People will pay what they want to pay, whether it be $100, or $1000.
I've also found that I, personally have overpaid for certain guns I really really liked, or have been after.
I've told myself tons of excuses to overpay like "there might not be another oppertunity to get one of these in person," or "This one is very unique because of......" Its really a mental thing, IMO, why people pay X price for X gun in X condition.
Also proves true from somewhat recent guns too. Browning made several Winchester replicas like model 12, 65, etc and some of those copys in 98%+ condtion are fetching more $ than the MSRP (from a few years ago), according to blue book. My guess is that the originals are too expensive and hard to find, (for some), and now the limited production replicas have somewhat dried up and people want these types of guns, but there is no supply for the increased demand.