Your question is too broad. Which vehicle against which vehicle? The thing is today’s average driver drives an SUV or truck which is a literal tank in comparison, whereas in the 70s most people drove cars. The bumpers wouldn’t even line up (btw this is a modern issue between “cars” and “SUVs/Trucks”) leading to the bigger vehicle overtopping the smaller vehicle. Modern vehicles are also on average heavier and have better safety features. The only thing I will say is an advantage of an older vehicle is in lower speed crashes it has a better chance of being repaired then a modern vehicle that crumples, but at 70mph even solid steel will get wrecked (as will the passengers).

Also bold of you to assume a lot of these vehicles from the 70s can easily reach 70mph without shaking apart.