Why the series needed the "cataclysmic event"

One of my biggest concerns when I heard there would be a sequel to Korra was the technology. I didn't mind it in Korea, but moving much further into the future would have the series, for me, move too far away from its fantasy roots and too far into sci-fi territory.

Having an almost post-apocalyptic setting is a great way to reset the modernization and allow some of the primitive, fantasy elements to return to the series while retaining some degree of technological advancement.

Hearing this premise, I am way more excited for the series than I was before.