People resist new knowledge for fear of the changes it brings. In this sense, what keeps humans in the cave is the fear of changes and the stability that the cave proposes.
We can arrive at this answer because:
In summary, people are afraid of everything new and for this reason, they often prefer to avoid what is new and can modify what they already know, for fear of the consequences.
More information about what an allegory is at the link:
https://brainly.com/question/11415099