never got into Germany was because the German military knew they were defeated and a huge collapse was imminent. This is important because the "stabbed in the back by the politicians" narrative, while not invented by Hitler, was used extensively by him to undermine the democratic government.
Had Germany not sued for peace, their army would have been overrun in weeks.
I do agree with you that one of the reasons for the harshness of the allied effort in WW2, with their insistence of "unconditional surrender", was to prevent this untrue line of thinking to reoccur.
WikipediaThe stab-in-the-back myth (German: Dolchstoßlegende, pronounced [ˈdɔlçʃtoːsleˌɡɛndə] (listen), literally "dagger stab myth") was the notion, widely believed and promulgated in right-wing circles in Germany after 1918, that the German Army did not lose World War I on the battlefield but was instead betrayed by the civilians on the home front, especially the republicans who overthrew the Hohenzollern monarchy in the German Revolution of 1918–19. Advocates denounced the German government leaders who signed the Armistice on November 11, 1918, as the "November Criminals" (German: Novemberverbrecher).
https://en.wikipedia.org/wiki/Stab-in-the-back_myth