There is a significant difference between a setting created for use in a work of fiction, and one created for use in a tabletop RPG. Summarized, it's the difference between a focus on drama and a focus on gameplay. Let me show you by example what I mean.
Focus On Drama
The Solador project began about 10 years ago, during my last year as an undergraduate, when I read "Those Who Walk Away From Omelas" again for the purpose of writing a paper on it. It struck me then that the whole "forsaken child" concept would not actually work, but something that actually does go on would do the job: the deliberate creation and destruction of people into living icons that are then sacrificed as scapegoats when things go wrong. We call them today "celebrities".
So I posited a setting where the protagonist is the first such icon, created and promoted by the masters of a post-apocalyptic city-state who are trans-human immortals as a means of population control via fake religion. The icon-hero figure is deliberately turned into a celebrity, and thereby divorced from the normalcy of human life, and the people worship him as a demigod as they pin all of their hopes and dreams on him- and therefore blame him when things go wrong, not the immortals.
The story is how the protagonist breaks his conditioning, becomes the mask in earnest, and turns the tables against the immortals- and he does so by way of the intervention of a long-lost comrade, bearing him the thing he must have to make it possible: The Truth. By becoming in substance what he was only meant to ever be a false idol for, the protagonist takes the false religion and makes it into the true religion. The immortals get their comeuppance by the one angle they never accounted for--and they are not incompetent; they did account for everything that their mindset allowed--and are destroyed one by one because of that flaw.
Notice the emphasis of creation there? We're looking at elements to tell a story here. Some attention gets paid to things that the reader will not see, but only just enough for the setting to maintain verisimilitude through to conclusion. Furthermore, such things are confined to those relevant to the plot or meant to hook into later related works, and developed only as required to fulfill that function. Our primary concern is that all of the elements required to succeed in telling this story to the reader are present, accounted for, and will be ready for use when written.
Focus On Gameplay
When the Old-School Renaissance got started, I created my own setting to emphasize its merits. After reading the "West Marches" series at Ars Ludi, I set about making New Model Colony. Its major historical influences are the Thirty Years War, the English Civil War, and the early colonization of North America. Its major literary influences are Robert E. Howard, Edgar Rice Burroughs, and other pulp masters of the past- and I deliberately exclude Tolkien (and his would-be successors) from the influence list. Had Jeffro's Appendix N been out at the time, I would've used it to inform my creation.
My goal here was not to create an expansion region, mapped out and nailed down. Instead, all I did was create the first hub from which play goes forth and the area within a day's ride from that citadel. The map, as such, is a handful of hexes (and about half of them are water). Instead, I put time into defining the elements that would go into creating or adapting procedural generation tools (random encounters, climate shifts, where the valuable stuff is, etc.) and then put in the house rules or rule clarifications needed to ensure smooth play at the time regarding Frequently Asked Questions.
After that, it's noting what things are available to players' characters in that first fortified town. Major NPCs, availability of services and goods, difficulty in finding hirelings and henchmen, etc. This is information players need to know when organizing their expeditions into the wilderness beyond; the information here is logistical and economic, with a side of politics (as that becomes important later on), as befits a genre of gameplay derived from wargaming.
Notice the completely different emphasis there. I'm looking at two things: how to make running campaigns in this setting easy for me, and how to ensure that the setting has plenty of opportunities for adventure ready for players to capitalize upon. This sandbox is stocked; all it needs are players willing and able to make their own luck by seeking them out and going for them. No dramatic concerns apply.
Now you see why gamers, by and large, don't care that much for storytelling; the concerns driving gameplay are logistical, strategic, and tactical. They are not dramatic, and storytelling tropes come off as bothersome bullshit at best- and often go over like lead balloons. ("This is when the enemy reinforcements we totally didn't anticipate arrive. Refresh your buffs, and let the tanks pick up the trash before DPS. Lust here to burn them down fast, then back on the boss.") Especially in tabletop RPGs, players--not the GM--have to drive the action. The long-running tendency to push passive, reactive gameplay as if it were a story has done far more to damage gaming than anything the Jack Thompsons and Anita Sarkesians of the world have ever done. It's a fraud, and it's long past time it be punished as one.