[primavera♥]

^yeah but ayu's more unique songs aren't really received as well anyway. Just look at the list of fan voted songs for A Best Live. That's what people end up liking or preferring more it seems.
People don't appreciate or enjoy the other works as much usually. So it still wouldn't help her sales.
Of course, this is just what it looks like to me, I don't know all of her fans or the public.

There are other artists who don't dramatically change and still sell well. There are a lot of other factors involved.

Honestly ayu has a pretty varied doscography, even in the past 5 years, although I understand the ballad complaints. But that didn't save her. And it won't in the future unless other things change.