system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokemon] Why do so many trainers only train a single type of Pokemon?

It should be obvious to anyone that a team with some type diversity is much stronger, since your entire team wouldn't have a glaring weakness. But so many trainers seem to focus on one type.

I guess it would make sense that many people just catch the type that's readily available (like fishermen who catch Water types) and some catch their favorite type because they don't care that much about winning. But even highly competitive trainers, even many of the regional Champions seem to focus on one type. Why?
gpt
What's better, being A master of a balanced team or being THE master in one thing?

Also, because it's cool. Certain regions hold overwhelming percentages of similarly typed pokemon and not everyone is on a journey.

Not everyone is a combatant in the league, you'll even fight kinder-gardeners, regular gardeners, old people, cops, immovable children in shorts, and most of them are just having fun.