Sartre failed to overcome this assumption to fully grasp that humans are profoundly social creatures. His philosophy was defeated from the beginning by a view of humans torn out of the essential fabric of social connectedness. This is the ideology that has been foisted on us by a new class of people called capitalists who took control of societies over the past 300 years. To the extent that we continue to accept this ideology, we will inevitably be left at the mercy of individuals who gain power through cunning and violence.
It will only be in the bosom of self-organized, autonomous, and inter-related groups that will enable us to overcome the scourge of barbarism and allow for the full flowering of our human potential. It is also our only hope for survival on a planet that we are currently in the process of destroying with our individualist ways of thinking.