Self-inflicted existential threat, but existential threat none the less.

When the war went south for the Nazis, their leadership (driven by Hitler) became convinced that they were loosing because "the German people have become degenerated and weak" (not a direct quote, can't be bothered to dig through Nazi quotes). So they wanted to punish the people for that by going all-out in their war efforts. They sent children and ols people to die even though (or maybe even because) they knew they would lose regardless. They did use scorched earth tactics on their own land, leaving nothing behind, purpously so that their people would suffer.

Even in the days before capitulation, when everyone knew that the Nazis where done, they sent even more people in to fight and die in that lost war.

Tbh, I'm surprised they didn't spend more than 25% GDP on the war. Probably because nobody would lend them money at that stage and they have used up all their reserves by then.

But lucky us Central Europeans that they mismanaged so much and where so bad at basic strategy.