/jp/ - Otaku Culture

Well, she has anime, merchandise, manga and other stuff being constantly made, and that's been going on for decades, so at some point, she just became an iconic thing, just like Mickey Mouse.
A brand cultivated over many many years gains a life and identity on its own.
The best part is though that the Sanrio company does still create other properties.

I wouldn't mind seeing Kitty White somehow be referenced more directly in SB69, though.