I submit that it is very relevant. You've closed off agency by restricting the discussion, when, in reality, you are doing something social with a small group of people.
Really? That how my point is going to be dismissed? Because I choose to deal with the issue being raised in this thread by having the group talk about and more importantly establishing an atmosphere where everybody feel comfortable pitching in.
By dint of reducing the scope, you've eliminated entire kinds of RPGs from discussion -- ones that do not so limit the scope.
Definitions and philosophy aside let's talk specifics. In your mind what I or any other participant are able to do that my take doesn't offer? What agency they have?
For example under my approach,
Player A: "Hey wouldn't be cool to have a campaign where everybody is part of a temple?"
Me: "Yeah that sound cool. Everybody good with that"
Group: "Yeah that sound fun."
Me (to Player A): "Do you have any ideas on what kind of religion the temple is part of?"
Player A (and Group): Have a discussion about which religion I have in my setting would be fun to roleplay. Settles on the Goddess of Justice.
Me (to Group): "OK here the material I have currently on Delaquain. It a bit thin in these area especially on temple life. If you have any ideas this a good time pitch them."
Player A and C: "We have some idea, we will work on it over the week and get with the group to see if it works out."
Me and the Group: "Sounds good"
Following that we hash out those details and then the players generates characters and their background. I answer any questions they may have. I in turn will generate the specifics of life around the temple incorporating the details the player come up with along with my own ideas. Then after the backgrounds are done, I incorporate those details.
Then the next session we start playing and I describe the initial circumstance and we go from there using the process I described in earlier
posts on this thread. Incorporating feedback from the players and the group along the way.
The "product" of doing things this way is some background on the setting, background on main locale the temple, background on the religion, and each of the character background which will have elements involving temple and religion and elements that involve the larger setting.
Contrast this with an example of the other approaches you talk about. If it helps it doesn't have to involve character centered around a temple.
However, agency, in and of itself, isn't not a good -- it's a point of reference only, and how it is valued is related to many other things and personal preference. More or less agency isn't a value statement, it's an observation that, with other things, can allow an individual to deploy their preferences more accurately and make their own value statement. For example, I play and enjoy 5e, so for me acknowledging it has less agency than other games I might play is not indicative of my valuing of the game. I don't really like FATE, but it has more agency than 5e, so that more agency is not really indicative of my valuing of that game, either.
If I wasn't clear I get that. The issue I have is that traditional roleplaying have less agency when it comes to actual play. That the point I am disputing. To be clear, my contention both have it, it achieved in different ways. That the way the games you mentioned handle work better for a sizeable segment of our hobby. Enough that it now it own niche. That both are subject to the vagaries of small group dynamics. To points like "fairness", "impartiality", "sportsmanship", etc are equal important to both. Finally that system can't fix this.
But to resolve this debate we are at the point where we need to talk specifics. What people do in actual situations. Then we look at their behavior and see how it work with my thesis or yours.
That said, the kind of agency you're describing is pretty much the baseline for an RPG -- the ability to play-act your character or declare actions for your character is the default position. It's present most everywhere, and where it isn't, it's exceedingly obvious -- you don't have to search for the difference.
I disagree that my approach is the baseline. I get a lot of pushback on many of my points on sandbox play from traditional roleplayers. The baseline is the use of the tournament style adventure. It gotten better but the general expectation still appears to be that it is polite to stick to the adventure that the referee has chosen. Time and time again, I have to tell players do what your character would do, don't worry about what I have prepared. Sounds like I am not the only one that needs to get up to speed.
It is limiting, though, in that the player can only ever express their character within the confines of the GM's chosen setting constraints.
Is real life is limiting because we are bounded by the laws of physics? Yet people seemly achieve many things despite that.