Shitty solder in wiring. Plastic for things that used to be aluminium, aluminium for things that used to be steel.
Just cost cutting by value engineers. I remember reading that the 3rd year of a cars model was probably the best, as they'd worked out the kinks in the design and hadn't watered everything down much... I couldn't back that up if you wanted a source, however
Tl; dr - a mix of value engineering and consumer preference. You wanna buy a $3k TV, or a $700 TV? How rock solid does your automatic sprinkler really need to be, compared to a satellite radio in the Sahel?
Per IPC industry standards, there’s three classes of electronic workmanship/quality control used:
Class 1: It works, just about. Shoddy soldering is okay as long as connectivity is maintained. Passing a QA test may be as simple as “it runs when powered”. This is where most consumer grade stuff lives: calculators, watches, flashlights, etc.
Class 2: Better built with generally more QA. Testing usually involves actually checking for function and different modes. Generally used only on commercial/civil government stuff like traffic lights, power controllers, heavy machinery - anywhere where reliability and longevity is worth paying more for.
Class 3: Complete process control and 100% coverage function (and almost always) burn-in/stress test cycles. Top quality and cost, typically only used for military, aerospace, or medical - where stuff failing means people die.
We bought our current car used years ago with a similar philosophy - it was the first year of a new change, and they hadn't changed or recalled anything in the few following years. Combine that with a one car owner locally, and it obviously was a good buy at 17 years old running strong.
But I will say even the best car makes, models, and years have their lemons. You have to look hard at each car's history and evidence to really win. We got pretty lucky.
Compressors fail way too often nowadays. The higher priced old ones were built sturdier and if they didn't fail in a year because of a defect they run almost indefinitely.
The idea that they never fail comes from survivorship bias.
All the control boards are always a popular thing to fail. They always cheap out on the components and out the board where it's done get moisture damage.