Your article is a useful deconstruction of a term that is the cornerstone of our business. Unfortunately, even "lowest-available-expected rate of return" is stilll as mythical as a unicorn. "Mike's" comment addressed the time issue pretty well. To go deeper into the rabbit hole, though, isn't it really the "lowest-available expected rate of return that I can find at this particular moment and is really my own opinion"? On a practical note, if T-bills cease being the consensus risk free rate, then a new label should be very much on the agenda for the academics out there....

David Hume and Immanuel Kant would have a field day on this. Fun stuff. Thanks.