Much of these tricks comes from how cars used to be constructed. Without any concept of safety cages, they were basically a bunch of very light structures secu

Much of these tricks comes from how cars used to be constructed. Without any concept of safety cages, they were basically a bunch of very light structures secured atop a heavy metal frame. So long as the actor remains on the seat above the frame, they are in a falling house of cards. Today we build the frames around the people. Pull such a stunt in a modern car and you will be trapped amongst twisted metal rails. Cars were also much simpler to take apart. A few bolts here and there and a couple people could remove an engine. A few more and the roof came off too. Today, it is all spot welded and tight tollerances. Removing any substanial part of a modern car, anything beyond the seats, requires planning and specialized tools.