Rushia and Coco joining a new corporation won't be a major change to vtubing. They built up a reputation by working for Hololive (the biggest vtubing corporation) and therefore made them more likely to be superchatted, which is why they were the most superchatted vtubers. As far as the general public is concerned, Coco and Rushia are gone. Western vtubers aren't gonna end vtubong, Vtubers aren't idols, (You) are all just a bunch of mentally deranged unicorns who can't accept people moving on.