> On the other hand, central banks are constructs of sovereign states and can literally create money out of thin air, which makes the whole bankruptcy question take on a different dimension.
This is not true, at least in the US. The Treasury issues currency.
What the Federal Reserve can do (and has done under QE) is perform an asset swap. An asset held by a bank (such as a treasury bond) is purchased by the Fed and held on its balance sheet. In exchange, the Fed credits the bank with a reserve asset. This reserve asset can not be spent in the real economy. It is locked in the banking system and can only be used within it.
Reserve assets are not money. They're much more like a utility token. Therefore, the US Federal Reserve does not print money under QE.
But there's the fact and then there's perception. Many are either unaware of how QE actually works, or think the distinction between currency and reserve assets doesn't matter. So they behave accordingly.