Different people in different areas have different views on the value of what they own. New Yorker's are no different. Maybe the price of vintage phones are higher there. They likely added in the eBay fee's to the price to maximize their profit. Dealers are in it for profit, they aren't going to give it away. As for the shipping, they have no control over the cost. Unless they offer to ship for free or a fixed fee. Now if you were to walk into their shop, I bet you could haggle out a much better deal.
As for the date, not all people know how to read the date code of a phone. All black rotary phones look the same to the average person because they where made the same way for years.
It would be like trying to date a Model "T" Ford which were made the same for years. Useless you have been taught the difference you wouldn't know.
Maybe they should have done a little research. If it sells, good for them they made some money. If they get no interest in it and they are a dealer, they will figure it out.
Just my two cents.
Can you add the eBay link?