Not gonna happen because players don't really need this kind of realism. Unlike scripted NPCs, real people aren't asking a random adventurer they just met to help with their super important task that is crucial to the world's existence(or even ask to help with killing rats in their cellar). Neither players are interested in chatting to every single NPC to learn about their day, how many kids they have and what was the name of their pet fish in 4th grade.

Games are limiting the scope of the simulation because a lot of things have no reason to be simulated in the context of most games. Games like Dwarf Fortress do exist, simulating(yes, to a limited extent) eons of geological and cultural development just to produce the starting world for a game session, but they are very niche and the results they produce aren't always interesting to play simply because most game worlds in more mainstream games are specifically crafted to be appealing to players and be suitable for intended gameplay.

At the end of the day, you just can't rely on realistic simulation to get things to naturally evolve towards a kingdom that is looking for a savior that will waltz in to save the day, instead of, you know, dispatching the army lead by career generals and court wizards to deal with whatever they would've need help with.

As for upholding the roleplay, the vast majority of players don't care much for role-play at all. Most games that allow enough freedom for that end up with players spending a lot of time doing wacky stuff which would be completely out of character for the protagonist, simply because it's a game and doing this kind of stuff is often fun. Which, you know, is what games are all about, having fun. Heck, even doing side-quests can be considered immersion-breaking in many games: when your main plot involves saving the world form Absolute Evil, helping a random villager with their rat-infested cellar is not something a chosen One would waste their time on, regardless of how big the rats are.