I'm not sure, I think (as in Nazi Germany) it was in the public conscience that acting in this way could not continue forever. To a certain extent, people were brainwashed into following ideology - especially in Germany's case, where after the death of Hitler and the invasion of the Allies from the West and Soviets from the East, the mindset of the populace became 'the game is up' - suddenly shame descended and ensured generations of Germans would find it hard to accept or justify the actions of their nation.
I can't second guess whether or not the Japanese people would act in the same way, but I think after the devastation of two atomic attacks, then a hypothetical third on the capital, would likely leave the nation on its knees - perhaps not in surrender, but in no way to fight.