What you're saying applies to private households and companies. It doesn't necessarily apply to a government that issues its own currency.

Just look at the debt ratio of Japan. For that matter, look at the modern day US which also uses a lot of debt to build up its army.

The point is, blanket statements such as yours have been shown again and again to be false, at least in that generality. I can only reiterate that you have to look more closely at the details to judge each situation.

As it happens, I read quite a bit about Schacht and Nazi Germany. They spent around 15% of GDP in the army in the years before the war. And they created an enormous external debt for that, because they needed lots of raw materials they didn't have internally (oil, rubber and many others).

In the USA, military spending is just a little above 3%.

Japan's economy stopped growing years ago. Their debt is mostly internal. They pay for what they import.

If you need resources from foreign countries and can't pay for them, printing your own currency can only help for some time.

The US certainly hides debt well. The reserve status of the currency keeps money out of circulation, keeping inflation at bay, and we “borrowed” trillions of dollars by overcollecting payroll taxes in exchange for future social security payments.

Hopefully things play out well.