Blairite 3rd way centrists like Kamala or Starmer or take your pick of any 'social democrat' around the world since the 1990s, almost all have claimed they just 'have to' abandon the working class and 'who cares because they have nowhere else to go so they have to support us': 

"oh we can't do left-wing populism, it would be unpopular!" - approval ratings / vote shares crashing to like 30/20/10% 

Mexico under the left-populist Morena party: 80% approval rating.

Left-populism works and is popular. Social democrats who have been flailing in centrism should try it sometime!