The other possibility here is that by persisting in this, we’re exhausting our capacity to respond to future crises. Of course, if one waits around long enough, another crisis is bound to occur. When that happens not only will we be short on ammunition (e.g. if the next crisis started tomorrow, we’d be going into it from ZIRP/NIRP and with already bloated CB balance sheets), we’ll also be approaching it from nosebleed levels thanks largely to the fact that we never exited the state of exception instituted to cope with the previous crisis.