Bang down the risen nail - keep the citizens in line and the empire on the rise.
Japan has always had a bit of a superiority complex. It's plan to bestow the heavenly flower of Japanese rule on the rest of Asia was utterly crushed by the H-bomb. Then in the post-war years they achieved economically what they had failed in to do in war. In doing so they fell under their own spell, in love with Japan again they couldn't realize the boom would one day fizzle out. It has long been the twilight, a social and intellectual wasteland; we're in the fallout, it's snowing radiation, but everyone is wearing short sleeves as the date is July 15th and it's officially summer - how can there be a nuclear winter when the calender explicitly states it's summer.
The unfaltering belief in the greatness of Japan has been the seed of its demise - to me it truly is a nation with tragedy hardcoded in it's psyche. It is constantly in a state of denial.
If Japan fails to evolve, unless it embraces individuality and change, it will become extinct, a fossil or fragment in an archeologists notebook. In that sense the pictures of modern day Japan in the film are like recorded fragments of a bygone culture.