In The 100 there is a rich history in the Grounder culture and an understanding of how things happened on the Ark. For a series that spent so much time building and evolving the world, some things managed to go unnoticed.
Aurora may have had good intentions in staying with Octavia in The 100, but she doesn’t seem to have thought about the long-term repercussions of her actions.
It may have been a good conclusion that Clarke was reunited with her friends at the end, but the transcendence aspect only comes up in season seven of The 100. There isn’t even a hint of such a thing during any other part of the series.
By the final season of The 100, the universe had been established, so the transcendence story came out of nowhere and didn’t fit in with the rest of the show. It seems to come out of nowhere for the sake of a massive ending. That was not the expected conclusion.
The Grounder culture would only have come into existence ninety-five years before the pilot episode of The 100. Except it takes time for rituals, laws, and other such details to be decided.
If only a few generations had been born since Revelation One in The 100, why doesn’t anyone know their story? Nobody told stories of what the Earth used to be? How did a world become as specific as it was in just ninety-five years or less ?; there are many questions that render culture meaningless.