BT is in a particularly bad situation. The geography that resulted at the end of the last invasion left the island pretty mangled. Rio's position and geography gave it a nearly insurmountable dominance in the region. The area it is in now used to encompass four realms, and part of a fifth. That dominance in the south leads to a particularly bad situation for Rio, in that they have no competition. They overshadow the south, leading to stagnation. The north, particularly the north-east, has a much higher density, and thus, that's where the action is.
