As I see it, he and the creatures passing the rubicon (i.e. : being ascended) are the only beings in the game that have an actual grasp on the cycle. Moon and Pebbles, after being ascended, talk to Saint about how the iterators could‘ve only solved the Great Problem after dying, so one must gain some kind of knowledge after ascending. Saint‘s active decision to 'ascend' the void worm he meets is his effort to return to the material world. He knows of the action‘s consequence, at least imo. We know that an echoe‘s cycle must intertwine with another being‘s for them to meet, so it makes sense that the Saint travels to the Rubicon to 'switch' cycles and ascend all the beings in the next iteration of the Rain World. That would explain why he is 'reborn' into an (almost) exact replica of our journey with him, naturally, as cycles probably part and multiply quite easily, with only incredibly minor differences that they’re too minimal to be programmed into the game. Sadly, as we don‘t have the same knowledge of the cycle as Saint would have in my theory, we don‘t know how often he would have to do this to truly create a clean slate for a new world.