I really don't see any evidence for this.
You don't need to, and I wouldn't expect you to, as our experiences, expectations, and preferences around TRPGs are radically different.
But there are no paths, let alone paths leading to the same place. In those games, I (as GM) am not the sole or even principal decider of what happens next. That is determined via action declarations and action resolution.
The GM decides what happens if the PCs don't do anything, and the GM decides how the world reacts to what the PCs do; and paths are sometimes visible (if not obvious) in retrospect, because all we can see looking back is what happened, not what could have.
The mechanism that you are positing seems to pertain to a game that lacks robust action resolution mechanics: you refer to the PCs acting in ways to change the fiction, and then you posit that it is the GM who reacts to those actions with the first thing that comes to mind. But where are the players' action declarations? If those actions are being declared, and they succeed, why is the GM getting to make up whatever fiction s/he likes?
I dunno. "Action declarations" seem kinda implicit in "actions" in a TRPG context, and as I said above, the GM gets to decide how the world reacts to what the PCs do, whether they succeed or fail.
This is actually very consistent with what I posted upthread:
I don't know what systems you are familiar with besides D&D, but it seems - on the strength of what I've quoted - that you're not all that familiar with systems with robust action resolution.
I'm most familiar with D&D, sure--5E is what I've been dedicating brainspace to lately, but I've played every edition from 1st through Pathfinder (skipped 4E because none of the groups I was playing with gave it a go). I've run Fate, for about a year--everyone seemed to be enjoying it until things accrued and I abruptly wasn't--and I've played it some outside that. I've played some CoC, some various White Wolf style games, some Champions, a lot of Mutants & Masterminds 2E, and smatterings and handfuls of other games. I've bounced hard off (in the sense that I don't particularly ever want to read anything about them again) Gumshoe (specifically Esoterrorists), Apocalypse World, and Blades in the Dark--the last left me particularly irked because I
really wanted to like it, but didn't, at all (on reading).
I think it's just--as I said--that our experiences, expectations, and preferences are so radically different that we end up talking past each other, and I at least find that immensely frustrating, because it never seems as though you understand anything I say.
That's not a strong advertisement for the utility or importance of GM prep!
I dunno. I feel much more confident as a GM if I've prepped things, even if the PCs go off and find/do other things, because I've thought about where they are and where the game-world is, and I'm better able to improvise. Also, it was more a dig on my own writing than a comment on GMing.