>>544032231
Between the way Monitors/Halos are prone to error leading to a situation like Delta, all the Covenant ships that didn't make it to Earth and fled from High Charity due to the Schism and Gravemind, as well as Earth having many places to hide Flood like that giant Forerunner structure, I always felt Chief's "It's finished" carried a different tone from Cortana's in that he was prepared for it to just be "for now".
Plus at this point Marcus and Marty have both alluded to plot beyond the Ark (whether after H3 or the intended H2 plot he didn't say) that would require more time to tell the story than just 2 more average length Halo campaigns could handle, however, just like some of those past builds and storyboards neither are at liberty to fully disclose those plans just yet.

>everyones
I suppose the Gravemind's return is all but inevitable