>>189579961>The black arc made it obvious that his life is tied to shin.
I think the question of what extent is a valid question, since discounting Old Kai (who was sealed inside the Z Sword), there were 5 other Supreme Kai alive before Buu's Rampage (North, East, South, West, and Grand). Is it not possible that most people are simply unaware of the fact that he's still alive inside of Buu, especially considering that it's a revelation to the people that literally went inside of (Super) Buu and yanked people he absorbed out like a power cord out of a socket? It'll be nice if Daikaioshin and Beerus get to interact either way. >>189580015
This makes the most amount of sense to me, since Buu was either still sealed or destroyed in the future while Old Kai wasn't mentioned, and thus can be assumed to still be trapped in the Z Sword. If being sealed affects the process, then Shin would be the only one that needs to die.