I agree with you, but crashing a 50-year old car also isn't the same as crashing a new car. Rust, failed fasteners, etc has to bias that crash to make it even worse for the old car.
Did you see that bel air in the video? It is in beautiful condition as far as I can tell.
Besides, things like rust would make the car crumple more not less and the issue is that the car doesnt crumple enough (in the right spots) so I imagine rust in the frontend could actually make it safer ironically.