The last game I really saw this at play was Oblivion. Even though FO3 and F:NV had the same engine, they didn't nearly do it in spades or try to plug in as much emergent gameplay. (In Oblivion you could leave a poisoned apple around and put it on top of someone's plate and wait for them to eat it; it was a bit janky, but there's no equivalent in games hence basically. Also in Oblivion, much like the Ultima games of yore, you could follow NPCs around and watch them go about their day. Though you do have to hear their short bark dialogue all the time "HAVE YOU HEARD ABOUT THE HIGH ELVES?" In FO3/NV/Skyrim/FO4, unless they are one of the explicitly-intended-to-be-regional-merchants, they basically do a small orbit in one of a few rooms that may or may not involve a bed.)
Like Boeroer says, there's a huge cost component. I would also venture to say the vast, vast, vast majority of players in Oblivion never noticed or took advantage of the "real world" elements of gameplay (as evidenced by how buggy and janky the poisoned apple mechanics could be), so I don't think people really are missing out on anything.
Deadfire is more reactive than PoE1 in this respect, and you could tell how far we are from the RPGs of yesteryear by doing a google search for something like "Where is Una in Deadfire?" People just aren't used to the idea that a merchant might actually go to sleep at night. Also, despite the fact that I have nostalgia for Ultima games (though mostly 7 and Underworld), I'm pretty ambivalent about this frankly, even the little bit that is in Deadfire - even though it's just a few button clicks and a short wait, I find it a bit annoying to have to wait for daytime so that some of my vendors appear (anecdotally, my wife--who is really into first person open-world RPGs and never grew up playing the old cRPGs--really hates ever having to wait for anything or trying to remember people's schedules). As another example, rain introduced RNG and almost botched my Ultimate run (and screwed up another; rain causes people to seek shelter; if you're planning on trying to steal or sneak and it's time sensitive, having everyone seek shelter right next to the thing you want to steal is extremely inconvenient).
I admit I was a bit surprised by how both PoE1 and Deadfire were generous with quests. You could flat out refuse a quest, and you'd still get a journal entry. But players hate botching quests or missing out on content because they didn't do the right RPG voodoo (either correct dialogue response or right stats). I think this is part of the continuing "streamlining" of game mechanics in an effort to lower barriers and broaden appeal across much of the RPG genre while reducing costs. Unlike the immersive component above, this is one aspect that I am decidedly less ambivalent about and miss more. I think stats and decisions should be meaningful, and that should pertain to more than just combat or ending slides - I want more explicit tradeoffs like the Bardatto vs Valera questline, or hard checks to even get a quest like in Fallout 2.