1870/71 was really more about nationalism on both sides than about governments or states. The latter were the players, but once the war was set in motion, they were floating on a current and only capable of minor corrections.
The French government surrendered, but the French simply kept going.



WW2 was everywhere about pushing so far that organised (and thus effective) resistance became impossible.

The Italians knew there was no way to resist any more if the enemies can even invade your country like that.

The Japanese leadership understood it couldn't go on after losing the ability to import material, with obviously determined enemies readying for invasion. The Japanese people knew their cities were ashes and obeyed the emperor (whose voice they heard for the first time when he told them to stop fighting).

The Germans of 1945 were really first and foremost fighting for comrades and fleeing civilians, or simply because fighting was deemed less horrible than being caught and executed by MP or taken POW by Russians. Especially the resistance in the East in '45 was more of a screening operation for fleeing civilians or an attempt to keep some escape route open for almost cut-off comrades than anything else.


I'm obviously not into theorising about breaking spirit (or "will") any more, not even about Clausewitzian disarmament; instead, it was quite often the loss of the foundations for successful organised overt resistance which meant ultimate and acknowledged defeat during WW2.
The will to resist with organised, overt violence was regularly broken when said violence served no purpose any more for want of a scenario how it could lead to a more acceptable outcome.