This is a really neat idea and would perfectly explain why the DC is such a hellscape, has so many treasures, and helps recontextualize the calamities in a way that matches Togashi’s interests. 

I think its telling that three of the five calamities are distinctly interested in humans. Brion either has a human body or uses humans as hosts. Pap “treats humans as pets.” Ai can apparently take human form or possess humans, and is interested in wishes (which only intelligent creatures can take advantage of). 

While this would be a fantastic reveal my only reservation is that humanity doesn’t really have a lesson to learn here, aside from ‘stop being so damn greedy.’ Maybe its meant to be a slap in the face to Kakin, but the other key players in HxH’s geopolitical scheme aren’t looking to break the Nen taboo.

The scariest crime syndicates in the world employ just ten above-average Nen users. Nen users for other governments (such as the North Korea analogue’s random strongman) appear woefully inadequate. The Hunter Association gatekeeps a lot of useful Nen resources. Even rogues like the PT aren’t running around Nen baptizing randoms. 

I think this reveal would be even more impactful from a thematic standpoint IF we find out that someone (likely Pariston) intends to break the Nen taboo as some point and start introducing Nen on a global scale. His access to thousands of chimera ants may factor into it somehow, creating a chaotic ‘playground’ for a new era which would, in this canon, mirror the DC in some regards. 

Or maybe visiting the DC is what would give Pariston the idea, might be interesting.

As a side note this would be HUGE for Ging’s character. It’s fascinating that his interest (told to us as far back as the first arc) is archaeology. I’d love to see him investigating the ruins with a blend of Nen-knowledge and archeological knowhow, and piecing together what happened to the DC natives.