What simple macroeconomic model should we use today?

The most widely used simple macroeconomic model has well-known characteristics: I n the short term, there is a trade-off between growth and inflation and a crowding-out effect: a demand-stimulating policy leads to a rise in inflation ( this is the Phillips curve); a n expansionary fiscal policy financed by public borrowing leads to a rise in interest rates that reduces private demand; In the long term, there is a dichotomy: inflation is determined by money supply growth; the equilibrium between the supply and demand for goods and services (between savings and investment) determines the real interest rate. But in contemporary economies, the characteristics of this simple macroeconomic model no longer appear: In the short term, the return to full employment does not bring back inflation; a systematically expansionary monetary policy enables an expansionary fiscal policy without rising interest rates; In the long term, money supply growth has no effect on inflation; real interest rates remain steered by monetary policy. It then has to be admitted that: It is no longer clear what determines inflation, in the short and long term (labour market rules?); The role of monetary policy is markedly more important than in the simple usual common macroeconomic model, including in the long term.