No ones talking about the lore in the Sinnoh library
https://bulbapedia.bulbagarden.net/wiki/Sinnoh_myths"Long ago, when Sinnoh had just been made, Pokémon and humans led separate lives.
That is not to say they did not help each other. No, indeed they did.
They supplied each other with goods, and supported each other.
A Pokémon proposed to the others to always be ready to help humans.
It asked that Pokémon be ready to appear before humans always.
Thus, to this day, Pokémon appear to us if we venture into tall grass."