My guess. Japanese have long valued mastery and specialization. Historically a cast society, people were expected to dedicate their entire lives to the line of work their biological or adopted family was known for.

The country also went to great pains to isolate themselves so this system continued for much longer than other parts of the world where sources of wealth were more diversified. In Japan wealth came from being known as the best at your craft, which fostered a culture of continuous improvement.

In much of Asia perfection of art was seen as a sign of sophistication for the wealthy. But the cultural revolution in China really dampened that for much of China’s sphere of influence.

After WW-II Japan was forced to modernize. Western manufacturing and improvement processes came in. The manufacturing was new but the culture of continuous improvement and mastery was already well established in Japanese culture but didn’t exist in the West where modernization was really a battle between the use of slave labor / child labor vs machines and the concept of continuous improvement was a new thing.

But I wonder, can we say the same about German engineering vs Russian engineering?