Or... Maybe it's because they think they're gonna die in the event of a crash. https://youtu.be/xidhx_f-ouU
My car is no less safe today than it was 24 years ago when it was manufactured. Twenty four years ago, nobody would have had a problem riding in this car.
Yes, crash test standards have become far more rigorous since then. That doesn't mean my car suddenly became a deathtrap.
I think the argument is that 24 years ago it was a deathtrap, and it still is one today. That being said, I also drive a deathtrap
I think people assume that a car is closer to failing as it ages or maintenance is being skipped. Some things, like an airbag, need to be checked and replaced after a number of years. If people think you are not financially secure enough to buy a new(er) car that you are also not able to keep up with maintenance (which is the number 1 cost people I know try to save money on).
I've driven in older cars with friends which were bought out of neccesity rather than choice. If some part died or broke they kept on driving, if it was possible and/or reasonable. I also hailed a car a while back where his brake lights weren't working as well as one headlight which was dead. He looked me dead in the eye and said the car would receive a checkup in a couple of weeks, he'd deal with it then. No brake lights, at all...
Edit:
I also thought of a "problem" which I had a few weeks ago.
So, I use a brand of shampoo which is anti-dandruff and not too expensive. It's hard to come by and the only local shop which had it at a reasonable price went out of business. So, my supply ran out and I googled. Found a webshop which sells smaller bottles for €1,- each (still cheaper than the shop) so I wanted to buy 10.
As I got to the checkout page, I noted €6,75 shipping. Damn, now it's more expensive than the shop. So I poked around a bit and appearently you can get free shipping on orders over €35,-. Since they didn't have anything else I needed, I'm now stuck with 35 bottles of shampoo :D