To clarify, I'm looking for titles like Mount and Blade, Space Rangers HD, Kenshi, and the Soldak developed games.

I guess you could call these sandbox rpgs. Games where you're not simply walking down a hallway, but rather enjoying each room in the house as you see fit, and maybe the neighbour's as well.

From the examples you give, I guess MMORPG are out of the equation, right? Project Zomboid lets you do exactly that. ;)

Well GOG hasn't bothered updating the offline installer for a while so there's that.... I've also been waiting for NPCs like every other old fan :p

I haven't played your examples so not sure exactly what you're asking, but I can't think of a more "living breathing world" than Ultima Online.

I've heard Dwarf Fortress is pretty intensive that way. So long as you don't mind a screen filled with ASCII characters as graphics.

World of Warcraft was the last one. Anything up to 2004, which is WoW release date. WoW now is a garbage mobile game practically. Blizzard totally ruined it with sticking to hardcore raids and buring crusade was a 7/10 expanison. Every expansion since is 5/10. So that is everything up to 2004.

Funny thing is, I haven't seen one rpg dev up to 2004 say something publicly and if they have nothing intelligent. If you look at these forums, or any other, there is noone who played the game in 2004 who posting anywhere. It's all these Fusion Console Zoomer/Millenial, CSGO players.

Kenshi should deliver on just that i belief
the newcomer wildermyth is also pretty dynamic though more on the character progression/interaction side of live

Cataclysm: Dark Days Ahead and has already been mentioned, Dwarf Fortress Adventure mode

overview of the former
overview of the latter