[Corvina]

Success is relative to the scales you measure with.
Even if you want to believe those numbers from the concert mobilisation report, Ayu achieved that with three different tours. Which is still awesome she could do after all with her fans!
Kuu only did a FC tour and a small regular tour last year - and over 90% of those dates were sold out, she still played for around 105k people with it.
She surely could have done more dates, but she also has a family and needs time to rest. And she and her team are planning long ahead usually (they roughly planned till 2021 already), that needs time as well.
DNA Tour also had other things going on like a nation-wide cinema release and two time-limited cafes.

And with sales - well, the music market nowadays is too segmented to only rely on physical.
DNA did well enough on streaming sites e.g. it got daily number one on Line Music.
Younger generations tend to not buy physical CDs anymore and Kuu had a viral hit with those last year and the Japanese media reported she gained a lot of young new fans with that.

It's hard to compare cause there are a lot of factors.
But for sure Kuu is on a rise again, while Ayu is relying on her current fanbase.

And the big difference is - Kuu and her team are usually clearly communicating to fans what to expect.
Ayu and her team are not.
That and also a quite unprofessionel approach for certain aspects in recent years.
That's how you disappoint fans.
Or at least that's why I am disappointed.
She doesn't have to constantly tour or release anything.
But be open and professional about it, about your career and brand.
Sorry, just frustration thinking about it.