* Strong regulation on energy use by appliances (modern fridges are much, much more efficient than ones from 70 years ago)
* Extreme competition from companies all over the world
* Consumers who care more about convenience and cost above all else, and reliability basically not at all
These 3 are why modern appliances are not as reliable. It is not a conspiracy. It is not lazy manufacturers. It is pressure from consumers and government that made things this way.
Take HVAC, which is a great example. Regulations have required far greater efficiency. So what happens? You get things like variable-frequency drives. These can slow down the fans in low-load scenarios. However, they also add another failure point. And speaking of fans, many evaporators now use plastic fans instead of metal ones. And guess what? They crack a lot more than the metal ones ever did. But they're lighter and thus more efficient.
It's like that with everything. Just take a look at modern clothes washer agitators compared to the old ones.
The other problem is really with consumers. All (the vast majority of) consumers care about is convenience, cost, and looks. They want a fridge that has the ice maker and the water dispenser, stainless steel, french double door, etc. They don't care about the reputation of the brand - they just buy the cheapest one that fits those checkboxes. That leads manufacturers to cut cost as much as possible - especially since they now have to compete with companies all over the world with cheap labor, which 70 years ago was not nearly as true.