That said, I realize that you have difficulties understanding different perspectives than yours, and as such I unreservedly retract my comment that apparently mischaracterized your opinions as follows:
1. RPG theory helped you;
2. RPG theory is essential to good game design; and
3. You believe in the theories promulgated on the Forge.
I'm going to advance a related position to the one you claim
@pemerton holds
1: RPG theory has helped a
lot of people including me.
2: RPG theory is essential to good game design; designing something without a plan is always going to end up with a mess
3: There is no one true RPG design theory any more than there is one true car design theory. A Tesla roadster, a Volvo estate, a flatbed pickup, and a Formula 1 or Indy 500 car have very different designs and the theory as to what makes a
good car (as opposed to the laws of physics they work with) is extremely different. And none of them would be good replacements to for the others.
In the case of the Forge you can more or less split Forge theory into three categories:
1: RPG theory that is right about RPGs as a whole
2: RPG that is wrong about RPGs as a whole
3: RPG theory
that is talking about the types of games that most of the people at The Forge wanted to play and not always generally applicable.
To me the success of the Forge (and unlike
@Umbran I see it as an overwhelming success) is down to part 3. The Forge coalesced around people who were looking for a couple of specific game styles and were not well served by existing RPGs. Most of them had come from a 90s White Wolf background, having rejected D&D out of hand for not promising to be what they wanted and been completely disappointed by White Wolf games for promising and not delivering (a big part of the thrust of the Gamism part of GNS theory is "Hey guys, what those D&D players are doing is actually pretty cool even if it isn't what we want to do")
And the successes of the Forge have been in two categories, both promised by Vampire and not delivered. Games for narrative change (the sort
@innerdude says he doesn't think happen, but Fate does to an extent and Apocalypse World is good at; My Life With Master was the first to do this) and games pushing directly for emotional investment by clean rules prioritising your relationships (Fate does this of course, but so does anything Powered by the Apocalypse, and many of the more famous and infamous games like Bliss Stage).
Essentially The Forge worked because it was looking for
chunky pasta sauce in a world with just smooth and spicy - and they knew they were looking for something like chunky pasta sauce. But part of the point of chunky pasta sauce is that it's not what everyone wants; some want smooth and some want spicy.
If we want a new Forge the question is "What do people want from RPGs that is not being delivered well"?