I am ignorant of the deep aspects of Japanese culture, but my suspicion is that it's a high-pressure society that uses shame heavily in the false belief that shame is a motivator. In reality excessive shame generally produces withdrawal, demotivation, and depression.

Combine this with the demographics -- it's very hard for young people to work their way up in an elder-dominated culture -- and you have a recipe for irrational expectations followed by shame and withdrawal.

That's my outsider suspicion.