> It still seems to me, however, that at the end of the day there's a net settlement process which happens at the central bank
There is a daily settlement process via central bank, but you do not need to settle daily. Imagine only transaction today was me sending 10 bucks to your bank account. Your bank would likely say that hey, pay that 10 bucks (plus interest) some day later when there is a bigger payment coming. And by tomorrow someone from your bank paid to my bank 10 bucks, so then there was no need to do transfers. Banks do run credit lines against each other. Obviously, if I were to send one hundred million bucks, your bank would cough and say that okay, let's see when the money is at our central bank account....
> I don't think this would constitute a run,
If there is a long term systematic and significant outflow of money from a bank, that is definitely a bank run. Banks can't create central bank money, so if my bank needs to send daily money to your bank and is not receiving anything back, it needs to start liquidating some of the assets.
> I'm finding it surprisingly difficult to Google this, would love any pointers you can give.
Unfortunately I have found very little good information on money, these thoughts are just based on lots of thinking on the fascinating thing called money... Most sources belong to two camps:
1. Basic , naive economics that is saying that money is created when I deposit money and then bank lends it to you so that you have the cash in hand and I have the money in the account so the amount of money is doubled in society
2. The ones who think they are smart and say that hey, that naive theory is false. Actually banks just create money with double accounting wizardy and loans. Or something like that.
The first one fails to capture the technical details of money creation and the second ones fails to capture the economics.