while in concept it’s a nice idea, it’s never worked in practice. case in point SimCity. you COULD play alone and have the entire sector to yourself with 4 small cities but the problem comes when
A: do these cities always run in real time? if so how do you effectively manage multiple real time hearthling villages with their own population of unique hearthlings, unique landscape, resources, monster invasion conditions, etc.
B: if it works more like simcity where individual cities aren’t running in real-time how do you effectively manage those standing still cities while in another city with out pausing another city in turn and slowing progress across the board for everything.
C: with multiplayer on it’s way eventually how do you manage multiple cities while in an online situation? would that be allowed?
D: what’s stopping you from simply sending all your hearthlings from a newly formed village back to your original village to better that village rather than working on a new one from the ground up and dealing with all of the problems that come with that?
E: how do you manage resources on a hardware level, CPUs can only handle so much at the same time, if everything is in real time that’s going to cause every PC on earth running a game with multiple maps at the same time to explode due to stress and if it’s not real time for all cities at all times that would mean constantly caching the current state of a city you’re leaving or entering to save it’s current situation and not lose said progress.
the list goes on with complications and questions that simply would never be able to be stomped out with such a feature implemented. the games too complex on too many levels to allow multiple maps running at the same time.