Give me your theories. Why would a company hate the 2nd biggest nostalgia machine it has? It's a cooler Kanto. But it has ZERO mons in Pokémon Unite at least on release. That's definitely personal.

I think someone on the team hates how Gold (and later Heart Gold) are always considered the peak of the franchise because it included 2 regions, people probably annoyed them a lot asking that feature for all games ever since and they want us to forget about it.