Wouldn't this make it so any story will always lack something to allow full agency? People will never fully be able to decide something on their own unless the story was being made right then and there. With prewritten stories, how close are we actually able to get it to full agency? How close can we get to the same type of agency explained at the beginning?

Does this imply that part of the enjoyment of games is building connections with others, even if those others are digetal?

This is one of the biggest reasons I love reading some of the books I do. I find it incredibly interesting when it seems like a character has no way out but then the author thinks of some solution that I would have never thought of. I feel like it also can add a sense of engagement if the reader tries to come up with a solution themself.