Depositors already have to cope with near-zero interest rates, but paying just to leave money in the bank would be highly unusual and unwelcome for companies and households
I wonder who are all those depositors that keep their money in banks at a near-zero interest rate? What sense does it make if you could just as easily (well, almost) buy US treasury bills (e.g. through TreasuryDirect) which are the safest dollar-based investment out there, thus securing yourself from a bank's arbitrariness?
Or do I miss something?
Treasury bills only make sense if you own a disproportionate share of them, or aren't paying U.S. taxes. The money for those interest payments has to come from somewhere, and that somewhere is a mix of inflation and future taxes. If you are an average U.S. citizen paying U.S. federal taxes, you might as well just keep your money at zero interest rather than taking out a T-bill and paying back your own interest--at least you'd save on overhead.
Or from another point of view, if you really think T-bills will give you a net gain, those T-bills are being paid back from
other people's taxes--which means you're investing in and enabling a textbook protection racket. ("Pay your taxes and we'll protect you from the bad guys. If you don't pay them, what you mainly have to worry about is us.")