To have a single individual keep their native universe "anchored" into existence, whether they realize it or not, and for their dimension and both everyone and everything else in it to gradually cease to exist either after they die or if they're unborn is just too heavy a burden for one person to have to carry. So, since learning that The Kang Dynasty would've pulled such individuals out of each of their realities and gradually see their worlds cease to exist, I think it's a good idea that that plot was abandoned in favor of Doomsday, in addition to Jonathan Majors getting the axe.