The Rand Corporation (and others) have done studies on this topic.WWII was more likely to happen precisely because no battles were fought on German soil.
The German populace felt like the German leaders had sold them out and they in fact hadn't been militarily defeated (specifically because the fighting never impacted German home soil). This led to public resentment . It's not that the term of the peace were too harsh (they were extremely harsh), it was that they were so hash that only a country that had it's ass well and truly kicked should have had to accept them. Your average German never saw any evidence that they had their asses kicked and so they resented the peace terms.
One reason that the US (and its allies) were so able to completely remake Germany, Austria, Italy, and Japan post-WW2 was that our military completely kicked their asses - we dominated them. Not just their military asses, their civilian ones as well. The civilians KNEW they’d lost the war BIGLY.
Not so much Japan - we hadn’t kicked their ass in the Home Islands; but, we’d sufficiently kicked their ass across the Pacific and fire-bombed Tokyo and other cities and nuked two cities and the Red Army was entering the war, so the emperor surrendered - once the Emperor surrendered, Japan acquiesced to all - including the post-war rebuilding of Japan (MacArthur was a GREAT Emperor of Japan).
The Rand Corporation’s studies indicate that if you want to engage in “nation-change” or “nation-building,” you first have to completely kick the nation’s ass, including making its civilian population feel pain for a prolonged period.
Look at Iraq and Afghanistan - our military toppled those two governments QUICKLY….the civilians felt little-to-no pain. They fought back for years.
I doubt the U.S. can fight a WW2 type war again……as the US moved into Germany, if a village surrendered (“Hey, the Nazi fucks are over there”) it was spared…..if a village/town had SS or Wehrmacht troops fire at American or Allied forces, the Americans (especially the Americans) and allies withdrew and brought up artillery and shelled the village into oblivion……it was a clear message to each subsequent village/town/city - surrender or we will blow your asses away…..we have plenty of ammo. We’ll launch 1,000 bombs to save a single soldier. Don’t fuck with us.
The locals KNEW their asses had been kicked.