Literature
Theories, Please #2: Ash Doesn't Have Time
The Pokemon anime is one that, for better or worse, gets fans riled up all the time. Most of the time, it's about the show's laughable assertion that their main character hasn't aged. But I'm not here to talk about that, I'm here to talk about how Ash trains his Pokemon, why he doesn't do it that often, and ultimately, why he can never win the big League Championship.
First off, I am not putting this down to a character flaw. Ash has shown that when he needs to do a specific type of training to beat a certain type of opponent, he is more than up to the task. I think of how in Johto after having his first battle with Clair ruined by Team Rock