Gotta ask whether the banking system makes sense in its current form. - Part of it is actually a utility. Payments, sending money from one place to another, making sure there's an account at the other end of that number. Everyone needs this, yet being a huge international network there isn't a whole lot that one bank offers that another cannot. - Part of it is deciding who to lend money to. Makes sense for the bank t…
While they make sense for consumers, our banking system is tightly coupled with another: mortgages. The money that you deposit is loaned out. Could the federal government do the too? Sure, and the government (talking about the US here) does end up owning a large chunk of mortgages via Fannie Mae and Freddie Mac.
But the expertise and the manpower around vetting the mortgages is a _lot_ of work. Work that the federal government couldn’t decide to take on tomorrow, might not even want to, and if they announced that they were going to try would shake the core of the stock markets. (And yes, stock markets matter for more than just making rich people richer.)
On the other hand you suggest de-coupling: “Find a lender.” If you take away the deposits, who has that much money to lend out without being dangerously leveraged?
If you were to design an economic system, this might be the one you’d design. Given the one we have, narrow banks are difficult to allow without some significant “turbulence”.