>>39637927My best guess is that Game Freak intentionally avoided her.
See, Bellossom, Solrock and Lunatone are all missing too, but all of them are referenced.
Bellosom is found twice in the games, and theres a side quest for showing an NPC the latter two if you send them in from Bank.
So it seems that Game Freak wanted to only include brand new Hawaii/Sun/Moon themed characters and Pokemon in the games, but left easter eggs and references to previous ones for fans to dig out.
In the same way, its likely that Pokémon like Klang and Lillipup wont be in Galar, with GF instead referencing them at most, and opting to design new Britmons like Galar-Weezing and Yamper instead.
So yeah two sides to the coin I guess, you can commend GF for wanting to bring new creativity to the regions and their inspirations and the types of pokemon and characters in them, but it also means they go out of their way to avoid the expected stuff that fans may have been wanting.