The reference is to Plato's allegory of the cave. Prisoners are chained so they are facing the back wall of a cave. Puppeteers project a play of shadows onto this wall and the prisoners, knowing no better, take this show for reality, when in fact, reality lies outside the cave. The OP was comparing the shadow-players to the professional cultural generators.
https://faculty.washington.edu/smcohen/320/cave.htm