Chapter 185, The goal of the war is the entire Green Valley Region!
The vicious cycle in the Green Valley Region was not a first-time occurrence.
In past years, every monster wave saw similar events unfold.
However, previous waves of beasts were neither particularly long in duration nor particularly large in scale.
Once the tide of monsters abated, the source of the vicious cycle would disappear, and things would start to improve.
Raiders were either eradicated or, in the territories they occupied, they would "whitewash" themselves and turn into legitimate plantations. Those who did not whitewash and continued as raiders existed as well, but their numbers would never be too significant.
Ultimately, when most people had enough to eat, the situation would gradually settle down until the next wave of beast tides, and the vicious cycle would commence anew.
In summary, that's how the people of the Green Valley Region got by over the many years.