Mate, live expectancy went up because of general improvements due to better tech.

Partially, but vastly more due to huge social safety nets, like free healthcare and education, housing programs, and more, which were only possible because the Proletariat was in control.

My fanfiction is what happened and happens all over the world.

No, your fanfiction is ahistorical. The socialists saved countless lives, the Nazis campaigned on genocide.