If someone decided I had to pay my entire mortgage tomorrow, I'd need an intervention of some kind. This doesn't mean I can't pay my mortgage. The banks have enough confidence the bank is solvent to risk losing at least part of $30B to prevent a bank run, which can be self-fulfilling prophesies.
We've seen stuff like this pretty recently in other venues; people were getting into fistfights over toilet paper in 2020. It didn't mean we'd always be short on toilet paper; it was a panic and short-term issue.
"perfectly good" in this case reads a little like "fragile".
We over optimize when things are good and then wonder what happened when there's a pothole. of course people are fickle and of course rates are going to change. Not being prepared for this is irresponsible.
The banking crisis really hilights why It's a Wonderful Life gets shown every Christmas.
The bank doesn't have your money in the vault, it's been lent out to other customers. Their loans can be in good standing and the bank can be perfectly solvent - but they can still have a liquidity issue if everyone wants to take out their deposits at the same time.
We've seen stuff like this pretty recently in other venues; people were getting into fistfights over toilet paper in 2020. It didn't mean we'd always be short on toilet paper; it was a panic and short-term issue.