A quick thought to complement the 'here to stay' thread.
Wind back to the 18th or 19th century and the gold standard. Gold is your base money, analogous to central bank base money today. Gold is risk free to the C18/19 holder of it, and it confers a 0% nominal rate. Sure banks will borrow it from you and pay better rates but that isn't risk free (since the deposit is not insured) so the rate you get from keeping the gold in your sweaty palm (0) is the risk free rate.
That was a system that was quite stable for quite some while. In more recent times we seem to have got used to the idea that t