>>35387274 Because most trainers just either:1) catch their own shitmon starter and train 'em to an high enough level so they can catch better ones
2) use Pokémon given to them for their professions, those would be bred by the corporation they work at. Which is the league in case of the gyms and elite 4.
3) borrow a shitmon to go catch a pokemon with chance to evolve strong, a la wally or pokespe yellow.
4) have a bought, bred pet with which they only fight a few times.
It's literally only like, 3ish dex holders per region at a time. Hence why there are three starters. In case of more than 3 dex holders, you get a backup starter which can be anything, usually a Pikachu or Eevee though. But some regions give Eevees to all their dex holders I guess.
