Think about when it was common to go to the car hangout or drive in restaurant and see people leaning up against their cars, or sitting on the hood or fender. Sheetmetal didn't seem to dent back then in a strong breeze or if you looked at it wrong.....unlike today. ...carriage return...
And for all of the tech advances and new lightweight alloys, cars don't seem to have gotten much lighter. Just think about car bumpers. I'm pretty sure the front bumper on my '64 Polara weighed 40 lbs or more just by itself. I never weighed it but when I took it off and while I was putting it back on I do know that it was heavy as hell. The back bumper wasn't much lighter. ...carriage return....
How much do new car bumpers weigh? It ain't a lot compared to those old bumpers. Look at how light fenders are now compared to back then.