Not sure about Kumiko, although I don't recall her speaking poorly about Utopia. I think with her, it's probably something personal, or she lost interest (which is doubtful?). A possibility is that she had to move due to her job, and getting internet after moving to a possibly rural area could be a hassle?
As for Bballin I think it's exams. It's crunch time right now for students (I am one) and there's lots to study for :s