How can the surge of populism be explained?

Populist political parties are winning elections or have a growing electoral weight for three interlinked reasons (we consider the examples of France and Italy): The economic situation is difficult, and a "normal" government would have to take difficult and painful measures to reduce the fiscal deficit, improve cost competitiveness, etc. The populist political party, on the contrary, promises to distribute more public money and raise wages, and this creates a more positive economic situation for the population in the short term than with a normal government; The beneficiaries of the populist policy obviously realise that it will lead to an impasse in the medium ter m (excessive fiscal deficits, worsening competitiveness); but they believe that the cost of the necessary adjustment will be incurred by others than themselves: the rich (who would pay more tax), and other countries (if there is a devaluation and debt monetisation or protectionism). This belief is of course mistaken.