[10 / 2 / ?]
This right here is the real reason for the culling. Because now GameFreak can cherry pick which ones to come back whenever they want. And people will cheer because they get to see X Pokémon again without GameFreak ever having to do any extra work. It’s like the Disney vault. We will never see a mainline Pokémon game again with a full dex as long as people keep getting excited when GF gives them a crumb after stealing the whole pie.