Why are all the Galarian Regional forms/evolutions of Pokémon from past Generations not in PMD:RTDX?

MrCarle

I knew that only Generations I-III Pokémon and all their Gens II-VI pre-evolutions and evolutions are present in Pokémon Mystery Dungeon: Rescue Team DX. However, unfortunately, absolutely none of the Galarian regional forms of Pokémon from all past generations or all their evolutions beyond this point are featured in this game? Now I wonder why you think, please let me know, thanks.🙂

CInnaBox

because those forms didn't exist back when the originals were made

I know you're talking about the remake, but the remake is like a direct remake, it didn't really add any post gen 3 stuff except for mega evolutions