Being built to be maintainable and parts shops being common also helped a lot of those things be maintained as well. They didn't even need to be as robust when replacing a part or two was cheap and easy. Now the issue is hard to identify due to complexity and finding replacement parts is so expensive or time consuming that just replacing it is less of a hassle.

Like I did basic maintenance for bearings and belts on a knob and switch only washer we bought in 2004. It lasted for almost 20 years with one service call to replace water seals because I didn't trust myself to get it right. Now we have a 3 year old front loading washer with a bunch of bells and whistles that have already stopped working shortly after the warranty expired that makes horrible noises which I won't work on because everything is a pain to get to and they are just way too complex.