The better analogy here would be the theories of psychology posited by Freud.
No serious psychologist gives any real credence to the totality of Freud's theories. But it doesn't change the fact that some of his basic constructs (id, ego, superego, etc.) became mileposts, or reference markers, for explorations into further research into human psychology.
Though the theories themselves are largely considered untrue, they provided a foundation, or baseline set of semantics on which to base further postulations. And no one apologizes for having participated in developing or evolving the theories, or having at one time believed them, or feels that somehow they've been a detriment to human progress, or that anyone who ever said anything positive about Freudian psychology EVER in the history of mankind should somehow be ashamed of themselves.
That's basically my approach GNS. I agree that the totality of GNS as a whole is at best a tenuous attempt at stringing together half-baked thoughts and self-referential definitions into some vaguely coherent theory. At its worst it self-righteously asserts its own veracity and presents its tenets as some grand theory from which we must all partake or forever be doomed to participate in bandwrongfun gaming. It's a mess, and I pretty much disagree with nearly all of its "top level" claims. In a lot of ways, it feels like Edwards is somehow trying to come to some rational grip with the fact that White Wolf games were wildly popular at the time, and he hated them, and the theory was somehow supposed to support and justify his own personal biases.......
That said, it has a few things I find interesting.
The Forge's "simulationist" theory is hmmm, how to say it without sounding overly negative, okay never mind, it's total crap. Edwards is clearly trying to build on some previous theories and differentiate it from the other two GNS "pillars," but it mostly just comes across as half-baked. It has definite undertones of, "Well, I don't really know how this works, it's something I've not experienced myself, but I can imagine it working this way because these reasons." His idea behind "High Concept Sim" is about the only thing that feels even remotely useful, but even then I think it's much more related to "story" approaches to gaming than "simulation," but Edwards can't possibly allow any hint of this "simulation garbage" to seep into his precious "narrativism."
It's my impression that much of the theory around "gamist" approaches are correct in principle, but basically miss the point entirely as applied to what makes a working, mainstream RPG, namely that Ron seems to think that "gamism" solely in and of itself is a totally valid approach to playing RPGs.....and I vehemently disagree with that assertion. Which is also why I disagree with [MENTION=3192]howandwhy99[/MENTION]'s approach to RPGs as well; RPGs have a "game" component, but if they don't have something else they're not a true RPG.
I think the general concept of "narrativist" theory/Story Now/player authorship is generally the strongest component---probably because it's the one they were trying to fix the hardest---but I have absolutely no desire to play any of the "narrativist" games the theorizing actually produced (Life With Master, Dogs in the Vineyard, etc.). I can see wanting to incorporate certain small "narrativist" components into mainstream RPGs.....but a wholesale "narrativist" game has almost zero resemblance to the kinds of traditional RPGs I enjoy. What does that mean exactly? I'm not sure.
So, in summary*: as a whole, GNS's broad-based claims are simply untrue. But I occasionally see bits and pieces and individual concepts here and there that can be useful under very specific applications, or might form an interesting basis for specific, situational mechanics in a traditional RPG format. And despite the theory's categorical untruths, it does provide a milepost, or marker for future exploration.
*Minor addendum--Other than the "White Wolf players are brain damaged" comment, I'm not familiar with any other controversy caused by The Forge and its adherents. There's some implication from Zak that Evil Hat was somehow responsible for creating some negativity in the industry. Can someone enlighten me?