1. Holo was never meant to go this far and it's clear from how wack some of the recent debuts have been from Gen 5 to IRyS to Gen 2 of EN. It feels like Yagoo only wanted Gen 0 to be it so then after the experiment ends he can move on to something else with VR. Granted he has probably made more money with this than he ever would have in some shitty VR game that would have never gone anywhere, but I also feel that he wanted to stop a long time ago and never did.
2. Coco left because she had no support, think about it as much as Kanata, Suisei, Towa and Watame all love Coco, none of them as far as we know really tried to make any sort of effort to make her stay, some could say its because they respect her decision as adults, I say it's because the other girls (and the rest of Hololive) couldnt or wouldnt do anything. Coco was basically 1 vs the world here and because of that she knew whatever battle she picked would be a losing one, she accepted that and instead of dragging anyone else down she just decided to leave. This also goes to the theory that Yagoo is just the Jack Tunney of our time and doesnt really do as much as anyone here believes he does.