Pikachu is one of the 151 original Pokemon introduced in the first game version from 1996, and quickly became an iconic character, the brightest star, present in every anime version, card, and merchandise.
After accumulating quite a bit of experience, most Pokemon species choose to evolve to increase their strength.
In the game, Pikachu is actually a pretty… nonsense Pokemon if `measured` in terms of strength.
Even if this Pikachu is a special case, it is still simply weaker than many other Pokemon.
If you are a regular follower of Pokemon, you probably already know that Pikachu was given the opportunity to evolve in the first part of the anime.
However, Pikachu dismissed this option and was determined to defeat Raichu with his current strength, and he actually did it.
In total, the two traveled together across 7 different continents, competed in 57 badge battles, and won 40 badges.
Indeed, with such impressive achievements, it is hard to criticize Ash and Pikachu as incompetent and useless people.