[Corvina]

I agree with you, Koumori.
From the way she handles her career in recent years and what she tells us in interviews, she seems to be perfectly happy with where she is right now, having decent popularity and making her fanbase happy.
Every time something good happens, stuff sells out, she gets compliments or a good ranking, she's always so humble and thanking everybody, almost a bit shy.
She likes to challenge herself and do what she wants (while listening to her fans), if she gets praise for something it always feels like it's just a by-product.
For Megumi no Hito e.g. she didn't even know till somebody else told her. Or her being a Twitter trend - her fans told her in the comments she said, she didn't notice before.

Could she even be more popular again?
Maybe, if she'd find that niche between urban and K-Pop, but maybe not, looking at the other very popular acts in Japan like Aimyon, Gen Hoshino and Kenshi Yonezu, who are basically the direct opposite of her.