>>54466636The Pokemon were never extinct in the first place, that was some dumbass headcanon Poketubers came up with, and /vp/, being full of underage children, just took that as fact.
Pokemon is a series of retcons, when a Pokemon gets a cross gen evo or regional, that Pokemon isn't newly discovered, it just always existed.
Hisuian forms are Pokemon that were discovered in Hisui, that's literally it, out of all of them, the only one that actually makes sense to be extinct is fucking H-Electrode and even that's prolly just hanging out somewhere.