[Corvina]

Hm, sales did drop a lot after her first album,yes. But they waited so long to release something different after Gold, it was kind of expected.
Also I don't really know if it's just about sales - Countdown and Welcome to Jas Vegas both charted in Top 60. She's pretty much tied with Ai Otsuka currently with sales and positions. Also there are singers, who have actual problems even to get to that nowadays (Anna Tsuchiya with her last mini e.g.). Though all of those are with avex. I don't know how harsh Sony is.

It would be sad, but she still can go indie if everything goes wrong.