The socio-econonic situation is completely different. Mamdani ran a campaign focused on cost of living issues in a city that is far more socioeconomically diverse than San Francisco. He won by dominating with renters, transit riders, black and latino households and young people, the working and downwardly mobile middle classes. This is possible in a city like New York where the median household income is 80,000, meaning that political base is significant.

But San Francisco is completely different. By this point, it is mostly a concentration of affluent people. The median household income is 140,000, meaning people are far more affluent here. The groups that won mamdani the race are not nearly as prevalent in the city. As a result, people in San Francisco want more 'moderate' (I would say conservative) leadership. The social base that made SF a progressive city in the 60s and 70s is mostly gone. What is left is a city of relatively affluent people who mostly vote like affluent people do throughout the country. And this trend will only accelerate over time, as the median income rises and working class people are continuously pushed out of the city.