The ECB published a Working Paper recently (September 2021) – Monetary and fiscal complementarity in the Covid-19 pandemic – which represents progress in the narrative. While the technical model that the ECB uses is just an ad hoc attempt to reverse engineer the reality so they can claim they can explain it, what is useful from the exercise is that the old mainstream narratives that fiscal policy is ineffective in providing permanent boosts to real output (or that austerity does not permanently damage the growth trajectory) can no longer be sustained. The taboo surrounding central bank purchases of government debt because they cause accelerating inflation can no longer be sustained. The claims that fiscal deficits drive up interest rates can no longer be sustained. Now the public debate just has to reflect that reality and we will have made progress. Of course, this is all core MMT – we knew it all along!