Let me explain. The PUBLIC SECTOR is in debt. It won’t be able to continue borrowing on the same terms unless it prints more money (leading to inflation unless done during a crunch of the money supply due to defaulting private sector loans etc).
Even before this pandemic, by cutting taxes the US Government got larger deficits under Trump (after Bush’s $1.5T a year deficit, Obama era got it down to $500B only, and then Trump’s and Republican budgets ran it up again.) The public sector deficits add up to the debts.
The northern cities - forget about it, they can’t even print their own money, and they shus down their businesses - they are screwed.
Now, everything is relative, so US sovereign debt instruments compete against, say, China’s in the open marketplace. But, there are alternatives to US treasuries - like Bitcoin and cryptos and gold etc.
If banks start to keep those as reserves, then the public sector and central banks will have decreasing power unless they FORCE the banks to have higher reserve requirements of base money that they print.
Btw in the USA, the vast majority of dollars is issued by banks (to businesses whose cashflows back this money supply, so bailing out businesses is a priority for the economy).
People are taking all that fiat money being sent by the government created by banks and plowing it into assets, which the government doesn’t have laws to seize, dilute the value of, etc.