Well Ash is gone now, and it's not really relevant anymore, so who knows. Lots of Mythical Pokémon stop getting referenced after their movie/arc. Meltan and Melmetal aren't even allowed in any games besides GO, Let's Go, and Sword and Shield.

But many characters in Paldea have Pokemon that rarely appear.

Look at this 😂😂😂😂😂🤣🤣🤣