I think the Nazis mastery of propaganda and mass marketing assisted greatly. Nazis wanted to brag about themselves to anyone and everyone they could, making all kinds of stylized films and creating an image of aryan perfection. That isn’t to say Soviets weren’t proficient at propaganda or didn’t make attractive art… as a matter of fact Soviet art can be quite beautiful and modern. But the brand image of “Look how strong and beautiful our pure blooded people are. Don’t you wish you could be just like us?” is more alluring than “Class solidarity” or oddly homerotic paintings of Slavs and Chinese men embracing