>>55077330Gamefreak has often referenced previous throwaway lines with new designs, or outright foreshadow new Pokemon or regions before they debut.
You're basically asking why don't all potential Pokemon that will ever exist exist right now, which is impossible to do. The Safari zones are already examples of "non-native" Pokemon, considering Pokemon like Tauros and Kangaskhan weren't caught natively in Kanto. Pokemon like Crawdaunt and Yungoos are also explicitly stated to be from foreign regions.
