>>58132978 (OP)
I don't think you guys understand that in the lore, Charizard, Machamp, and Gengar aren't specifically "from" Kanto. They're found in Kanto but aren't exclusive to there. In universe they aren't seen as any more Kantonian than they are Galarian. You're reading into this too much anyway, the real reason from a design standpoint of this poster is to not spoil any of the new Pokemon. It's the same reason your mom has a Munchlax instead of a Galarian Pokemon.