This terrifies Cover, not because it's competition in terms of profits, the active girls will always be making more and the girls who leave are doing it to chill rather than be super ambitious, but because it means that they're no longer the only retirement home option around. When someone wants to withdraw from the frontlines and just chill with their accrued fanbase, they now have a proven viable path, with avenues for merch, performances, management and also have a workable group of girls to collab with. After a holo has made full use of Cover to experience the idol dream, they can rest assured that they have options open to them, to either stick around, or to leave, and this is an existential threat to Cover's IP business. Management you better try real hard to appease anyone who's having doubts. Sure the concerts are a little scuffed and undoubtedly will never rival holofes, but I'm sure they're sufficient to satisfy anyone who no longer has burning ambitions.