[Corvina]

To be fair, she doesn't have to work anymore, it's her decision. Or maybe it's in her contract, who knows, though she talked about retiring in 2011/2012 when she married, so I guess she is pretty free with her career.
I've just recently learned, that apparently it's enough, if you have just one big hit at karaoke, cause karaoke revenue's are big enough to live from it.
Kuu already achieved that with Ai no Uta alone, plus her peak earnings and her well selling beauty brands.

In the post about mother's day this year, she also posted in the hashtags that she was very happy, that her son said he likes her lives and wants her to do it, cause she always fears he might get lonely.
But in the end she's the one in control, how much she'll do.