Then it won't work. The current iteration of Germany is fully based on having been bombed to get a fresh start. If you already have something, you won't change it. If you have to re-build, you will implement improvements. No bombs, no reset, no joy.
I am less confident about my predictions for an uncertain future. There's all kinds of ways different things could go.
I didn't say we needed to follow their example to the letter; it was just one counterexample to the "woe and ruin for 100 years" comment.
Germany wasn't a fresh start. The de-nazification ended up being a bit of a joke and (AFAIK) the first governments were full of ex-Nazis.
It is not inevitable that you come back improved. It is not inevitable that you come back at all.