I really think it's that she can't come back right now, not that she doesn't want to.
I've been observing and thinking...
Personally, I think it's highly unlikely that Aibon will return anytime next year (2007) or anytime well before her 20th birthday in February 2008, because of the simple reason that UFA would most probably NOT want to take the risk of her giving in to the temptation to smoke again and get caught again. Aibon, like all of us, is human, and also experiences temptations and stress from all kinds of internal and external forces; even if she has managed to abstain from smoking for the past 10 months (for which it's not possible for anyone to ascertain, except Aibon herself), and even if she swears in public not to smoke again before she turns 20, the risk of her giving in to the temptation for whatever reason(s) would still exist as long as she's alive; not even Aibon herself can predict what temptations she may experience before her 20th birthday in 2008 if she were to make a comeback in, say, early next year; and according to this:
50 Questions * 50 Answers: Kago Ai
http://smp.cyber-ninja.jp/50q-kago.htmlAibon has said before that she herself and her weaknesses are her rivals, which is like saying that she herself is her own worst enemy. So it seems that as far as UFA and Aibon are concerned, it's better to be safe than sorry for a second time...
But of course, surprises are always possible...
But then again, sensibly speaking, I don't think it would be sensible for UFA to let Aibon come back...that is, if she wants to in the first place...
In conclusion, although it's POSSIBLE for Aibon to make a comeback next year, I still think it's highly IMPROBABLE.