I was a Morning Musume fan in high school but the members of the group kept getting younger as they were replaced, and I kept getting older. After a while, it stopped making sense to be a fan. (They never did a song "I'm sad about only being able to contribute $20,500 per year to my 401(k)".)
I never got into AKB48; is that they problem they are having, or is it something else?