I always took it that GNS 'Sim' is about systems in which the environment is a source of constraints. Whether in Process Sim where the game may attempt to use mechanical and game design features to impose realistic real-world (or alternate world) constraints, or in terms of High Concept Sim where the game may attempt to impose or prioritize specific concepts and focus play around them. There ARE important differences, but each of the 'S' sub-agendas does share certain key traits. Playing in a way that focuses on those agendas tends to have key similarities for this reason. Again, I'd appeal more to
@pemerton here, as he seems to have all the relevant citations near to hand.
I think I understand the commonalities being claimed; I'll just again suggest that these commonalities range from trivial to irrelevant to people focused on "process sim", and often may not be much more so to people who really don't care about that but
do care about genre emulation.
Essentially, cats and dogs have a lot of common traits including being mammalian predators, but that doesn't mean their similarities are particularly relevant to people who have a preference in one direction or another. So you have to ask what purpose your classification of them is actually serving.
That's been my argument; the narrowness of Nar's classification means it served some actual purpose. Its not clear to me that GNS sim's classification really does.
Sure, and GNS also separates these things, while recognizing that they do share the trait of imposing constraints. While they may do so for fairly different ends, the means are functionally similar and lead to similarities in play, as well as (probably more importantly from Ron's perspective) similarities in game design.
I just don't really agree that they do. Again, genre constraints are a fundamentally story based concern; they're designed to produce a particular look and feel and enable particular kinds of stories. GDS sim actively rejects story as a reason to structure things in such a way.
I mean, GNS actually REALLY WELL describes 3e D&D! And for exactly the reason that its various agendas all seem to fall within 'S' primarily.
Its not the things a model successfully describes that is the sign of its value; its the number of ones it fails. It somewhat describes D&D because the latter tries to be all things to all people.
The way some people see it as a purist-for-system process sim,
I'd tend to describe that in terms that are not particularly charitable, to tell the truth. I don't think its really defensible once you get into its guts at all. I think the confusion about what D&D is doing is largely a consequence of it having been used as the all-purpose fantasy tool for so long people don't even recognize the possibility they're hammering nails with the wrench sometimes because they're so used to doing it.
I'm not entirely sure how, for example, GDS approaches explaining that. I'm not saying it can't, but TBH it doesn't seem to really go there at all AFAICT.
See above. I mean, honestly, to use a particularly well known example that originally set of GNS development, there were people who were certain Vampire was a narrative game, and banged away at those nails for all they were worth. As best I can tell, D&D for a long time (I won't speak particularly of 5e, though not much I've heard counters this) is a largely gamist structure overlayed on a genre focused target (with the note that its largely become its own subgenre), with some dollops of dramatist and simulationist fragments here and there. But most of the latter is vestigial, and most of the former is being done on levels that the game only passingly helps you with.