Although the heroships are exploring the rim of the 'area' colonised by humans, Earth is, in Casey's own words "intact, happy and prosperous." This was discussed in a Youtube video interview from March 2017.

Heroes back on Earth historically hid themselves from view behind masks and fiercely guarded their secret identities. On the heroships, as discussed at the start of that same video, such concerns are no longer necessary. Heroes are now celebrated and a necessary part of the team protecting humanity from dangerous aliens, some of which actually regard us as food.