A lot of the local yards are picking up abandoned vehicles off the streets by police orders, or they are buying cars that don't sell from auto auctions. Also most larger towns have yards where all the police impound vehicles go if they don't sell at an auction.
Most of these vehicles belonged to people that couldn't pay the fines, or towing and storage fees. For example, if your driving a nice ride and would get busted for DUI, the vehicle gets towed in, and is required to sit for at least 14 days at the impound yard. Towing and storage start adding up the day they tow your ride in, and keep adding up until you pay them cash for the bill, but you have to have the authorization from the police before they will release the vehicle.Depending on how long before you can bail your car out, the tow and storage can add up to a grand or more. (I know this because my shop was next to a towing company's storage lot). Once the storage time reaches a specific time period, the towing company can seek to set up an auction to sell your car. Since law enforcement and most towing companies really don't have space to store them very long, they have to go some place, and the pick a parts often end up with them. You and others get the chance to get a good buy on parts where there is little info about the vehicle.
i agree, with some cars and trucks, especially old ones, you really wonder what the real story is. It kind of saddens me such a nice vehicle ended up in a pick a part that is in better shape then the one like it I'm driving around, until I get to buy parts off of it cheap so I can keep my heap running. Then I'm not so sad. Gene