You ever wonder how regular animals could compete with pokemon for ecological niches? Or how come humans could survive in a world with superpower beings like pokemon?
The first one is easy to answer: there are no regular animals in the pokemon world
Yes I know we seen normal animals in the anime, but just like fruits and normal food has been retconed to poffins and berries, normal animals have been stricken from canon (see Lt Surge "the lightning amarican" it's now suddenly from Unova)
But more importantly, there's a pokemon whose existence makes it extremely unlikely that anything but other pokemon could have evolved:
Anorith
you see Anorith is an Anomalocaris, an animal so old that it's older than bones; internal skeletons woudn't develop for millions of years after Anomalocaris roamed the oceans much less fish, so yeah, in the pokemon world everything not a pokemon would have gone extinct way before the dinosaurs (which are also pokemon!) since they don't have supernatural abilities like pokemon have since that long ago
As for the second answer: humans can survive because of 2 reasons:
1-Humans themselves are pokemon
more specifficaly they are psychic type pokemon, consider how many humans we seen that have psychic powers, from gen I to gen V, plus the only pokemon we know that preys on humans (Chandelure if you don't know) is a ghost type which is super effective against psychics; the reason that most humans don't seems to use psychic moves it's because afters tens of thousands of years of using pokemon people have no need to use their powers anymore
There's also the alternate explanation that while humans are psychic types they don't learn psychic moves by level up so all their psychic moves (and probably aura abilities too) are egg moves
2-humans have an ability that make other pokemon obey them
Let's call this ability Tamer and it works like this:
Tamer: the wielder can order other pokemon around, fails if the target is a higher level that the user
this would explain why pokemon obey humans even if they abuse them and why higher level pokemon disobey their trainer even if they treat them kindly