Again, I think we just disagree, which is fine. Or perhaps we agree, but you are expanding that point of agreement into territory that feels to me not covered. I don't want to belabor the point. But I think railroad complaints is about players not being able to say things like "Okay we tell the duke to screw and go west instead". It is about feeling like there are rails on the adventures and no real other options, and the player feeling like no matter what their character does, it doesn't matter. But I don't think the complaint is usually made because the player wants something from the system in terms of power, like narrative control.
Set aside the idea of narrative control... because it is itself a muddy term. I mean, telling the duke to go screw and heading off to the west... that's an exercise of narrative control. It's the players saying that they're not interested in this duke situation, and they want the characters to go west. Surely this will change the narrative.
So, let's just set aside that phrase and instead look at it as what can the player do. In what way can they influence play.
I agree that this difference of how it is viewed is often at the heart of disagreement in these discussions, but I don't think that means we should limit the idea of player agency to your view. Why would we? There are other ways to influence the game beyond the character, and that's true of almost every game, even ones that want to limit things to the lens of the character.
So in the sense that it is about the players wanting to be able to decide what their characters do in the setting, I would agree. But if we are talking about things going beyond that, I think you are stretching how most people think of agency in an RPG
Again, I don't know if either of us is capable of concluding what "most" people think of as agency in an RPG. I can only speak for myself, and for the concepts that the words imply... which I think is not limited in the way you describe here.
I don't think railroad complaints about agency are a system complaint. They are a GMIng style complaint
Oh, I think complaints about that vary a great deal. I absolutely think some such complaints are system based. Look at the OP of this thread as something that pushes into that territory. It describes two games and their methods, and shows how one is susceptible railroading, while the other is not.
Systems absolutely matter when it comes to this stuff. There are some systems that allow for a wide range of GM methods... and those can be used to railroad, or can avoid it entirely... and in those cases, you're right, it's a matter of the GM. But the system has to be one that allows the GM to railroad.
And this is also why you see some variance in the idea of what even constitutes a railroad. Earlier in the thread,
@Maxperson challenged
@pemerton about his view of railroading as it applied to an NPC being "important". And setting the term aside, I think we can all see why such a description of an NPC may be questionable for some of us.
I don't think we are going to resolve this disagreement. But I think I am using a much more standard definition of the term here. And I think it is very reasonable to push back on a definition that seems to come loaded with stylistic preferences. I am not saying those preferences are invalid, but binding them to agency, muddies the water because it confuses a discussion about how the system approaches things like the power of players over fictional elements in the setting, with one that is really supposed to be about being able make meaningful choices in the setting.
I think your use is far more about stylistic preferences than mine. The term as I'm using it is the literal definition when we combine the two words player and agency. Yours limits it because you think of a player exercising agency in a way beyond their character is undesirable.
As for power of players over fictional elements in the setting and being able to make meaningful choices in the setting... I don't think these are different things. I think meaningful choices is one example of the power players have over the fictional elements.
But there are other examples, as well.