There are a lot of old "parts" cars out there that people are trying to restore. I think there is still a huge need for parts. You see these beat up cars changing hands frequently, as they are at the affordable or lower end of the price range. If you want to sell parts, make it easy for the buyer. There are several reasons things don't sell. A big reason the marketplace has become too greedy with asking prices. So what do you do...I think there are three options:

1. Sit on the motherload of parts and try to get rich with a high asking price
2. Sell for reasonable, if not below market prices and move the stuff on to someone who needs it
3. Dumpster

The third option sucks, but I'm sure lots of stuff is gone because of that. If you want to sell, regardless of asking price, you have to let people know what you have. Make an inventoried list of items. Part, year, make, model, price, etc. Take a photo of the part. Whether you sell here on Moparts, swap meet, social media or another website, people want/need to know want you have. Few are fans of digging through the bin of stuff at the swap meet. Its a waste of time not knowing if that part your looking for is there. Same with the post where there is hundreds of items in a picture without any real way to identify the stuff. Some are experts and can pick those items out, other new people in the hobby have no idea. I don't think shipping cost is an excuse. It is a hassle for the seller. People will pay to get the stuff they want/need. They may not gamble on a purchase if they are not sure its going to fit. Make it easy for the buyer and you can sell stuff anywhere.