Board Thread:Theories/@comment-26472215-20160222034906/@comment-24930713-20160223014249

I would imagine the people living in the Homeland either don't keep watch over all Titans, or they are just as susceptible to being overrun by Titans as the people within the walls. So that would mean that Titans roam freely around the world, gobbling up people left and right.

That being said, that(^) is not fact, it's merely my opinion on why the world is so empty. Early on in the series they make it pretty clear that Titans are only interested in people. As such, it would seem quite difficult, if not impossible, for people to live around Titans without some way to keep them at bay. Let's not forget, the only reason people within the walls are alive is because the First King created the walls to keep the Titans out. Without his interference it would seem like the only people left would be those inside the Homeland.

Also, I plan to re-read your initial post again so I can give a more in-line response to what you were asking about.