With a diminished reservoir of conventional policy space, it is much more likely than was appreciated in 2012 that, in  See Chair Powell’s address in Jackson Hole, Wyoming, last week (Powell, 2020) for an illustration of the revisions to the macroeconomic projections—including for the longer-run neutral federal funds rate—of FOMC participants as well as private and public forecasters.
Distortions can build up, and over time, the seeds can be sown for difficulties in the future for preserving price stability. Also, lax monetary policy can feed into a self-perpetuating lack of confidence in the drivers of economic growth. Eventual adjustment in advanced countries could be significant.