IIRC the devs commented on this once.
The gist of the response was "This is a world torn by a devastating war of gods, we
want the population of the world to deplete".
EDIT: I did a search and was unable to find any such response, so don't consider what I said as the official dev response. I may have imagined it, or maybe it was someone else. Either way, that's one explanation to "no natural growth"
