So, four pages can be summed up by saying:
Don't like the price, make an offer. If the offer is refused don't buy it. If it's cheaper new than used, buy it new. If you don't want the risk of used for a small price savings, buy it new. If you don't trust the seller, buy it elsewhere. It's called economics and price-capping is plain rediculous.
The only comparison between cars, guitars, and airsoft is that they're all subject to economics. Used car prices are representative of the value buyers place in them. There's a reason 5-year old Cavaliers go for $5,000 and 10-year-old Preludes go for $7,000; buyers place more value in that Prelude than the Cavalier, even though both were similarly priced brand new.