This mechanism makes sense when both the leader and follower believe that the race result is reasonably predictable. I would argue that the underlying reason for low interest rates is that progess is slowing in applied science and technology. New technology acts as a boost to some of the runners but the boost can be distributed in an unpredictable way that is not in proportion to their investment. When there is a random flow of unpredictable technology it is worthwhile to spread investment over many runners, the demand for investment is high and interest rates are high. Now that new technology has slowed to a trickle the race has become predictable and markets become concentrated, lazy and profitable.