The cave isn’t a place, it’s a mindset or belief. The prisoner who went “outside” disengaged from an established belief system and saw reality from a different, richer, perspective. The prisoners still chained would not accept another belief system, or tolerate a challenge to their views. This is how Plato thought of philosophers. They were able to look outside, but were often persecuted for their claims, or killed for them. Like Socrates, Plato’s teacher, and many others throughout history.
However, the other inmates of the cave do not even desire to leave their prison, for they know no better life.
I don't think I'd buy that. I think humans are just naturally curious about things, and would want to go outside, if for no other reason than to just look around.
I think you're right about humans being naturally curious, but we can be coerced or programmed into rejecting new information. The persecution of scientists, prophets and other people with different ideas can be seen as choosing the cave. The Matrix is essentially a modern retelling of the allegory of the cave.
