They are relatively easy to recycle, and valuable enough that "metal theft" is a thing. Remember all the rusted-out cars that folks had in their yards? They'

They are relatively easy to recycle, and valuable enough that "metal theft" is a thing. Remember all the rusted-out cars that folks had in their yards? They're mostly gone now. See "Junkyard Planet; Travels in the Billion-Dollar Trash Trade" by Adam Minter, fascinating book IMO.