>We're about to test whether they are. If we somehow manage to print all this money and nothing bad happens, then why not?

Fortunately, other states already have tried this, and shown that it causes immense economic harm. Specifically, we have the examples of Venezuela (53,798,500% inflation since 2016), Zimbabwe (peaked at 79,600,000,000% per month), and Weimar Germany (merely 29,500% per month at its peak).

So you should be asking, what if we manage to print all this money and something truly terrible, horrible, and damaging to the lives of everyone in the country happens? And what if it's something easily predicted by almost any economist and with massive historical precedents? And what if it sets the stage for genocidal dictators and the most violent war in history, as it did in the case of Weimar Germany?