>>58587910that "pokeball" on left? understand, it is not canon. There is no such thing as a 'primitive pokeball'. Before the invention of the energizing technology of the pokeball a human's only option was to avoid dangerous pokemon, typically. In rare cases, a human with enough guts, courage and luck could befriend a dangerous pokemon despite lacking the modern pokeball.
Before the pokeball there were no "trainers" as such but rather rare and exceptional individuals who, by way of luck and sheer will, successfully tamed/befriended a pokemon.