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.
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.
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.
It is not inevitable that you come back improved. It is not inevitable that you come back at all.