For Fauna's graduation, that wasn't the case, it's only supposed to be the cause for the other graduations. But i'm more and more doubtfull of that. If i'm not wrong, some graduated members said in their new life that it wasn't the problem.
Also, i'm not sure video game/chatting streaming is really a good way to earn a living. Only the very top streamers can make a living, vtubers are kind of small in comparaison and need to rely on merch or something else. And Hololive was providing those services that are hard to get when you're indie. And i'm sure streaming pay less and less, there is less and less viewers for that kind of content. And that's why Hololive whant to take the idol route. I seriously don't know why a streamer would want to continue streaming no matter what, and i doubt it's passion for professionnal streamers like them.