Do mainstream centre-left parties in Western democracies need to fundamentally change direction to survive?

Context

Centre-left parties across Western democracies—including Labour, the SPD, and the Socialist Party—have faced declining electoral support over the past two decades, losing ground to both right-wing populists and progressive challengers. The debate centres on whether these parties need radical ideological or strategic overhauls to survive, or whether targeted reforms suffice. This question has intensified as inflation, migration, and cultural polarization reshape voter coalitions that once anchored social democratic movements.