I think some people just like the attention having an old car sitting out gets them and they enjoy telling people it's not for sale.
There's a 69 Mustang here that I pass on my way to the beer distributor, it's under a tattered cover but the shape is obvious. I'm told it's a Boss 429 but some day I'm going to lift the cover to see for sure. I'm 46 and it's been in the same spot since I was in high school.