The answer about Mamdani seems simple

[AZProgressive]

6. I think Bernie Sanders already softened the edges of Democratic Socialism

There are many young voters that don't remember the Cold War that well where socialism isn't as dirty of a word as it used to be. (Off topic but Russia has the same geopolitical interests as they do when they were the Soviet Union but the right loves Putin)

I think that is why they tend to do very well with young voters compared to older.

Venezuela's economy was always heavily dependent on oil production. When they had Chavez and generating a lot of revenue for the state due to high gas prices he was able to spend on a safety net and improve literacy rates. When Maduro took over it and turned into a dictatorship he started keeping the money for himself. No matter what system of government we have it relies on the same humans.