As I understand it, a big reason for the massively improved consumer mechancial goods (including cars) is precision engineering. Basically, the ability to use computers (and other tools) to build devices to a much higher (more precise) spec. That's why in the last 25 or so years our consumer goods (including cars) have become so much more reliable. And car engines, in particular, have become so much more efficient.
Now, there is more complexity to many of these things, and complex things often run into problems, and there are more parts that are made of plastic compounds, which often wear out sooner than the metal components used in the old days. So, yes, your 2024 washer and dryer probably won't last as a unit as long as the 1970 washer and dryer, but during their operative life they will perform much better, and break down far less. The other part of the equation that has changed is that the relative cost of the machines to the cost of labor (i.e., the repair person) has come way down. It's not that you can't repair the machines, it's that for the cost of the repair, you can buy a new one (or very close to it). So why keep your 2009 washer, when for about 30% more than the cost of repair, you can have a 2025 washer that cleans better, uses less water and electricity (or gas), and is faster?
And, if you have it in you, a lot of the things that wear out (heating coils, springs, spindles, even circuit boards) are pretty easy to replace. I've replaced the heating coil in my dryer three times now ($15 part). Works great.
