Not always true. I know of at least 3 recent cases where people sold their restored cars only to see them destroyed.
Here's a 4th example I just learned about:
Quentin Tarantino Conned Collectors Out Of Classic Cars
March 31, 2007
Moviemaker Quentin Tarantino conned classic car owners while shopping for 1970 Dodge Chargers and Challengers for his new movie - because he couldn't tell the motor nuts he was going to trash their pride and joy.
The director launched a nationwide search for the rare vehicles and knew collectors would refuse to sell them if they knew he was planning to use them in car crash sequences.
He says, "One of the things that was told to us was `You can't mention that you're gonna destroy them.' They'll never sell them."
Tarantino eventually got hold of seven classic vehicles and trashed all but two of them. He adds, "At the end of the shoot there was one Charger and one Challenger that we never destroyed... and I wanted them, it was my movie, so I bought them. The mechanics went through all the other Chargers and Challengers and picked all the best parts and made a Frankenstein monster for me."
http://www.starpulse.com/news/index.php/2007/03/31/quentin_tarantino_conned_collectors_out_