Yeah, it doesn’t make sense to have all pokemon be available in one game. It’s not like you can find all real life animals in one region.Unlike Pokémon Sword, I can at least understand the lack of a full National Dex in this game; they're obviously putting more work into animation now, and the new textures are honestly gorgeous. It seems like they're also reworking the models of the Pokémon a bit.
That said, it's far from ideal and I really wish they end up making a main series title where all the Pokémon are back.
I like for them to rotate different pokemons per region so it feels refreshing. Instead of seeing zubat for the nth region replace it with woobat. A lot of pokemon are underutilized.