>>22633627First, she is doing fine unless you compare her to her own coworkers or Vshojo.
Now, if you are genuinely asking why she is not as popular as the other HoloEn: Voice debuff. Also, just like Matsuri, her most evident talent is only available on 3D streams which don't happen often.
The start of her vtubing career was not great either and not landing a good first impression is still hurting her numbers a bit imo.