I'll try and save you a Codraroll essay on this by summing it up as...
Nice try, but I'm not repelled that easily.
Pikachu being the mascot and easily recognisable face of Pokémon is one important aspect, true, but also keep in mind that the primary purpose of the Anime is not to recount the thrilling adventures of a heroic and competent main character. The Anime is mostly there to advertise the games. It shows off the world of Pokémon, presents its concepts, creatures and moves. Occasionally it also displays some legit useful tips and tricks, but mostly it's there to guide kids into the games.
For that to happen without too much spoon-feeding, the characters on the show have to learn stuff as they travel, similar to how a kid learns the basics of Pokémon as he watches the show. Every new Pokémon has to be presented as something new and wondrous, along the lines of "Oh, look, a Squibble!", because the Pokémon is new to the viewer. Whenever Ash and his friends encounter something new, their reactions have to match those of the viewer. What is that thing? What does it do? What moves does it know? How strong is it, in what situation? Ash and his friends find out over the course of the episode, and the viewer learns something new. It doesn't matter if Ash has seen the Pokémon before, or even had it in his possession for hundreds of episodes. It's new to the viewers, ergo it has to be new to Ash.
That all means that Ash must never be allowed to build any experience. The Anime "resets" periodically, so that new viewers can tune in and learn everything from the beginning. And so must Ash, because if he reacts with "eh, seen it before" they can't dump exposition. If Pikachu swept the floor with everything it encountered, new Pokémon would feel weak and useless by comparison.
There's also the aspect of selling merchandise. Cute and beady-eyed first-stage Pokémon can easily be turned into adorable plushies, hence why the main characters always acquire a few of them and never evolve them. Evolution functionally removes a character from the show and replaces it with a new one, meaning that once that cute, squeaky, beady-eyed thing evolves, it'll never come back. Instead you've got something that's two metres tall, full of spikes and speaks in a deep bass growl. It might sell merchandise too, of course, but those beady-eyed plushies are suddenly not relevant any more.
So yeah, if you want any sort of story out of the Anime, well, you're not in its target demographic. It's mostly a marketing tool, there to sell the rest of the franchise and explain its contents. Something that everybody can tune in to and watch without having played the games, but which crosses over just enough of the games that viewers will eventually want their own Pokémon experience. The Anime, despite being about a trainer who beats all eight Gyms and eventually participates in the Pokémon League, really only covers the first third or so of a Pokémon game. It only gives occasional glimpses of strong, fully-evolved Pokémon, hinting of their awesome power but never fully featuring them. Not only does this give the perception that they're really strong and awesome by setting the overall power level of the Anime to NFE levels, it also teases viewers that they can play with the strongest Pokémon only by buying the games.
TL;DR - the Anime is a commercial/tutorial aimed at little kids. Once you've played the game even halfway through, you're not in its intended audience any more.
