I don't have a strong opinion about whether they were / continue to lead in tech, but I do have a strong belief that Japan and its general culture does lend itself to a much stronger valuing of conscientiousness in work and doing things well / fully / to the best.
Maybe that's a bit of cultural myth of course, which the Japanese benefit from propagating. (All the movies, mentions of people who take decades to perfect their craft; even small everyday jobs being done well; things on time; everyone polite, considerate, etc)
But there definitely is something about what attentiveness to detail can achieve, when allowed to happen by emphasis of culture or the work at hand.
I don't know if I or anyone I work with every gets to be conscientious about doing something really well and to high competence. It seems that everything I'm involved in is "let's try it and see whether it works" and then give up and move onto the next thing. Or "well, good enough".
Which is good for some purposes and ends, but not good for developing a decades-long expertise, deep expertise and wisdom, about doing things.