Could it be…

A CONSPIRACY?!?!?!

The higher-ups pay no mind because they are being TOLD to by the homeworld gems themselves . I mean why else would there be a diamond on their currency and not the Illuminati eye pyramid like ours?

I don't understand this either, and it's clear that humans do have a concept of warfare an military in this alternate timeline, considering the use of war imagery by Ronaldo and the tanks in the dogcopter movie trailer thingy.

My headcanon is that, after the second World War, Rose stood in front of the world leaders and told them to not get involved, or she and her followers would stop them.

Still, you'd think there'd be some kind of human involvement in all of this. Why aren't there people exploring and studying the wreckage of the ships, or the artifacts?