the ‘it’ is not important, let me rephrase it to ‘your description sounds like you envision TTRPGs as giant state machines’
I'm not sure what you mean by this.
RPGs are games. They are played by participants, who - as in any game - make "moves" that cause the game to unfold/develop/change/progress. What is distinctive about most RPGs (and is true of all the ones I've seen mentioned in this thread) is that (i) the principal medium of play is shared imagining, and so the shared fiction matters to resolution; and (ii) most of the participants make their "moves" by saying what a particular character in the shared fiction does, while one of the participants (the GM) makes their moves in a completely different way, by presenting, to the other participants, scenes/situations that involve their PCs.
A game like GURPS has a lot of rules about how to represent, in mechanical terms, the stuff that everyone is imagining together. But - as
@thefutilist has pointed out - it has not much to say about how the game participants actually agree on what to imagine, or how the GM is meant to introduce the scenes/situations that the characters find themselves in, develop those scenes (ie work out
what happens next), and transition from one to the next.
It is this gap in GURPS's rules that opens up the possibility, that thefutilist has flagged, of keeping the GURPS mechanics but adopting the Apocalypse World rules for how the GM does those things.
not sure, they replace what used to be the class sure, but that doesn’t mean they are all that similar. The class defines abilities the character has, the playbook goes beyond that, it tries to drive a narrative / define the narrative role of the character.
The class-character can also attempt stuff that is not covered by an ability of their class. The playbook one has to stick to the moves of its playbook. That is why I mentioned TRRPG as a giant state machine earlier
Neither of these comments is true.
The playbooks in Apocalypse World establish character abilities - unique moves - just as (say) a D&D class does. Eg the Brainer can choose psychic manipulation moves, the gunlugger can choose shooting and fighting moves, the savvyhead can pick
doing weird stuff in a workshop moves, etc. The relationship between those moves and a "narrative role" is no different from D&D - eg the things a fighter can do in D&D suggest different ways of engaging the fiction from the things a thief can do.
And just as in D&D, so a player in Apocalypse World can describe their PC doing whatever they want. Unlike most versions of D&D, the
resolution rule is clear for all these action declarations: if a player move is triggered, then the appropriate move is worked through and an outcome generated; otherwise, the GM says what happens next , in accordance with the GMing principles which include the principles about when to make a soft or a hard move.