Talking about what imaginary people can do in imaginary worlds is of
no relevance to discussing the agency of players in a game.
A game is an event that occurs in the real world. It is a social event that occurs among real people. The event unfolds in virtue of the interactions among those people. And a game (typically) involves some sort of structure of interaction that the participants impose upon themselves - the rules of the game express that structure.
As in any social activity, involving interpersonal interactions, we can ask of a game
who is making the decisions,
who is driving play,
who is influencing outcomes.
As
@hawkeyefan posted most recently, and as I have posted repeatedly including not too far upthread, the decisions and outcomes in RPGing typically pertain to the creation of a shared fiction. (An alternative sort of approach is the solution of a puzzle by the players, where the fiction is more of a means to that end. But no one in this thread, besides me and
@Manbearcat, seems to be talking about that sort of RPGing.)
So when we look at the social activity of playing a RPG, we can ask questions like
who makes decisions about the elements that are found with in the fiction? (people, places, imaginary events, etc).
How does the group decide what happens to those elements? (eg what happens to the imaginary people and places, which imaginary events occur, etc)
If these things are done by discussion and negotiation, we can ask
Who has the most influence in those discussions and negotiations? This is something that
@Campbell has been very interested in for many years of posting.
If these things are done via a mechanical process, we can ask
Who gets to activate that process, and to establish its various inputs?
All these questions are relevant to understanding the distribution of agency in the real-world activity of playing a RPG. The suggestion that all episodes of RPG play answer them
the same way, or will reveal that every episode of RPGing has
more or less the same distribution of agency, strikes me as a highly implausible empirical conjecture!