system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokemon] who decided what the starters would be and why?

pretty much the title.  just to keep things in context, let's stick to the original 150.  in-game, they are about the rarest of the rare.  who's good idea was it to make bulbasaur, squirtle, and charmander the starters?  to give every newcomer to Oak's lab a choice of the three, there has to be some kind of Pokemon version of a puppy mill cranking out starter 'mons (or a really worn out ditto somewhere).  wouldn't it have been a better idea to give a bunch of snot-nosed greenhorns a rattata or pidgey or caterpie to start with, seeings as how they're ridiculously common?
gpt
>Every newcomer in Oak's lab

What are you talking about dude? I've been to Pallet town before and there were all of 2 houses there and one lab. There aren't really "Newcomers". I'd be surprised if there has been a person moving in that town for decades.

Considering their rarity odds are that these are just pokemon that the Professor had for research. He then completed his research and was kind enough to give some good pokemon to his grandson and a kid he's probably known since he was a newborn.