While I think it's good advice to keep what you have, and repair it if you can, that isn't a great option for those who don't have a good savings built up to pay for constant repairs, or those who can't afford to miss much work. It can be cheaper monthly to trade in and make payments on a reliable source of transport, and most people live pay check to pay check in this country. In other words, as a society, we've set it up this way.
A lot of advertising goes into convincing people that the new car will be more economical than fixing the old one, and people often have an easier time paying payments than dishing out 2 or 3 thousand a couple time a year for a repair. This is a fact. They may not be greedy, they may be house poor.
So, again, this socks it to the middle class, which is getting pretty wrecked taking so many beatings in this country. They will pay the price, and have some expensive broken down used cars to fix. They always pay the price of predatory lending, and predatory advertising. Americans are overworked, and underpaid.
I think it sucks for them, and it's indeed unfortunate that in a capitalist car centric society, you will often fall victim to it. There's a lot we could do to minimize these kinds of pitfalls for consumers if we weren't so reliant on making money off of the middle and lower class to the point of beating them down.