Since I've crossed over from game dev to doing illustration myself, I've realized something about how one ends up in this place, because I've been there. Not as deeply or for as long, but I've seen it and still get tempted by it. It's not actually unique to game dev - it applies to any creative work(e.g. the 30-year novel) - but games demand a higher degree of engagement with their technology than static works, and that creates the ground conditions for scope to explode far more frequently.

What actually happens when scope explodes is that a coherent view of the project has been lost. This is not problematic in a creative sense, just in a "finished product" sense: every time you introduce a contradiction into the work you have to either eliminate it(which creates a negative attachment response, and therefore really requires project managers to step in and cut off some heads) or you work very hard to create some kind of technical rationale, e.g. "we'll do both ideas, so now we have a new type of asset and the entire game must be populated with it and the features will be a little more complicated by it". Which you can proceed to start doing without difficulty, and only feel the downside of later.

Game devs are particularly susceptible to this because games sit in an intersection of dynamic/synthetic/interactive that allows infinite numbers of assets and features to be added, but at a gradually increasing cost, even if you drop fidelity(see every roguelike that has been in development for more than a few years.) And it lets the dev sit in a space of perpetual escape from coherence, because "it'll be great as soon as I add this next thing - after all, nobody has ever done this before". It's a little hype cycle that can be reinflated over and over.

But if you paint a picture, it's one-and-done: there's only so much room on the canvas, so you have to deal with your folly immediately to finish. You can, of course, go the route of burning it and starting over, making the same mistake repeatedly, but this provides much less of an illusion of progress than hitting the compile button on your ever-growing codebase. And you can do a lot of preparatory studies and meander without committing to the image you're making, but the act of doing the studies still propels you into a space where you can hurry up and finish whenever you want.

So the usual advice given to game devs to manage scope is to introduce a technical restriction that "limits the canvas," but if you're technically inclined I think the proper advice would actually be to limit dynamism and make more static works with simple design scope so that more of your technology can be one-off, and not required to be integrated into the large, fully-automated framing of a game engine. E.g. a magnificent rendering system that creates static images for a visual novel. "Simulator" type projects are mostly eliminated by this except where they can take a direct reference, like a vehicle sim. All of my least coherent designs started embracing the simulation concept - and doing that was itself a way of getting away from a clear statement of belief within the game, of trying to accommodate multiple sets of beliefs without directly engaging them.

Not that anyone is going to listen, of course. Sometimes one has to lose a few years of living to this stuff ;)