Even to us, that “fruit” has become a legend.
For the past centuries, it hasn't even “awaken” once.
This a part of what one of the five elders said as a reaction to what the government agent told him on the Den Den Mushi.
After reading that part of the spoilers and reading the whole spoilers my head-canon on it.. Was that Zunesha is in fact a devil fruit user that hasn't died yet and is at 1000 years of age and that's just why his devil fruit didn't reincarnate or why no one else got to inherit it.
(Note: I referred to Zunesha with "his" because the voice actor in the anime has a male voice.. May be the dialog in the anime or manga says otherwise so i could be mistaken)
Then why would the world government change Zunesha's devil fruit name
1. Because it is crazy powerful and whoever wields it could be very dangerous ( you saw what Zunesha did to Jack and his entire fleet back in Zou Arc ).
2. Because Zunesha has something to do with the void century and its devil fruit name hints something about a certain incident ( may be the incident where zunesha did a mistake and thereafter were forced to walk with Mokomo Dukedom on its back for 1000 years to atone for that mistake ).
what do you think guys?!