"They do this with motor assemblies too. Its not uncommon to see working sets of motors in japanese cars that are 30 years old where window motors and such would easily have failed in american sedans. potted, brushed high quality motors were a fixture on practically every japanese sedan in the 90s for even boring stuff like mirror adjustment."

I think a lot of that "over-engineering" gradually went away towards the 90s and beyond, as cost concerns and other aspects started to bite in. Plus, they also understood that people started to change cars more often than before, so why engineer something for such a long duration? A lot of that initial over-engineering was also because of the pressure on Japanese brands to try and establish themselves in markets like the U.S. and Europe, where there was a general feeling that these "puny" Japanese cars might not last long. In terms of over-engineering (I know, keep using this term), the true pinnacle for me was the first gen Lexus LS400 designed to compete with the Mercedes S-class. Now, that was something else.

Funnily enough, they have started lagging U.S. and European companies after the mid-2000s in terms of vehicle technologies like advanced transmissions, wider adoption of turbocharged engines, infotainment etc.

/just a few personal thoughts from my years working in the auto industry