"Can someone explain to me why most trainers in pretty much any pokemon game don't carry six pokemon?"

I recently started playing Let's Go Pikachu and it brought back so many nostalgic memories of Yellow. One thing started to eat at me though; every single trainer in the game with exception of late game characters like Red or your rival refuse to carry more than a few Pokémon for reasons I cannot comprehend. How can Brock call himself a Gym leader when you can carry six Pokémon yet he chooses to carry two? What's the logic in some Ace Trainers mind when they walk all the way into the middle of any route/cave/building and decide they are fine with the two Pokémon they currently have yet they want to challenge every person they see? Quite frankly everyone in the game except for you the player seems to actually know how to play the game/exist appropriately within a constructed world since that's essentially what you're doing in any game is diving into a created reality and existing within a set of parameters while trying to optimize the experience by utilizing everything you can. If in the world of Pokémon the idea of being a trainer means you will one day catch at least one of every Pokémon and maybe beat the Elite four one day or at least aspire to the idea these trainers spit in the face of that idea and apparently serve as nothing more than small points of experience and money that are designed to take you very little time to complete. I can't imagine the idea of ever losing to a trainer on the road at this point. via /r/pokemon http://bit.ly/2CJgOVr