Even before the COVID crisis, why the need for increasing economic stimulus?

The COVID crisis is an exogenous shock that has required the introduction of highly expansionary economic policies in OECD countries. But even before the COVID crisis, fiscal and monetary policies in OECD countries had become increasingly expansionary. What explains this growing need for economic stimulus? In fact, there is a vicious circle: The expansionary fiscal policy require s an increasingly expansionary monetary policy due to the increase in public debt; The expansionary monetary policy gives rise to increasingly frequent and extreme financial crises, which require s increasingly expansionary fiscal policies; the expansionary fiscal policies then require expansionary monetary policies, closing the vicious circle, as crisis recovery then sows the seeds of the next crisis; This mechanism is reinforced by the loss of potential growth that follows the cris i s and that also leads to the use of more expansionary fiscal policies.