Sort of related to the above:
It seems like so many of the Anime's problems could have been solved by making Ash the mentor. Let him keep a team of Pokémon, but put him in the background, and have a new main character for every region. The show is meant to introduce Pokémon to a young, wide audience, so the relatable main character has to be a complete newbie. Instead of giving Ash a lobotomy (and giving all of his Pokémon away) every time he builds up some competence, they could easily just start with a new, incompetent character every time. Ash could stay near the center of the show, and be the overarching main character who travels between regions, but he doesn't have to stay the star.
The problem, though, is the other big "requirement" for the show to function as it does today: The main character not only has to learn something new (new to the audience, at least), he also has to be the star. It's
his Pokémon that have to solve all the problems. The main character should stay in focus, learn new things and solve problems life (or the writer) throws at him. It'd be no fun for the main character to run away at every sight of danger, while competent, grown-up Ash handily solves the problem with his high-level Pokémon and years of expertise. For the main character to truly be the main character, he should also be at the center of every problem, and their solutions.
OK, but that sounds like it could still be done with a new main character, right? Just put him and his Pokémon on center stage, delegate Ash to the periphery, problem solved? Not so fast. For merchandise-related reasons, one of those Pokémon that solve problems together with the main character has to be Pikachu. The main character of the series and the franchise mascot have to be in the spotlight together. Pikachu always outside its Poké Ball, always visible on the main character's shoulder, the one Pokémon to be in every shot. To sell merchandise, the show needs to throw Pikachu at the viewers, giving it the most exposure and the most screen time. Pikachu has to zap the villains once every other episode, at least. That role can't be taken over by any other Pokémon (save for Lucario, I guess). The main character himself should also be marketable in the long run, nobody would buy lunch boxes or T-shirts picturing the main character from two seasons ago.
So... let's review the requirements: Pikachu needs to be the main Pokémon of the main character. The main character needs to be
"our hero", so the supporting cast can't be too competent, lest they solve every problem without the main character. The main character needs to be relatable to viewers that are not familiar with the games. Something new (to the viewers) has to be learned every episode. The main character can't be swapped out too often, or he'll "go out of fashion" and fall into obscurity.
By far the easiest - but not necessarily the best - solution to all these requirements is to keep Ash and his Pikachu around. Dumb down Ash to the level of the viewers every time a new region happens. Keep introducing the same basic concepts of the games at the beginning of every region. Pretend like the current "season" of the Anime is the first season, that you are always watching Ash's first journey. Very few viewers are going to watch the show for long enough to notice the pattern, and the show isn't meant to cater to those who do. Introducing
new viewers to Pokémon is the main purpose of the show.
So I guess the core problem is this:
The Anime is a commercial and a tutorial. That dictates how it is developed and written. It essentially pictures a guided play-through of the games, a sneak peek of the fun viewers could have if they bought and played them. It also keeps reinforcing the idea of Pokémon to non-playing viewers, ensuring that most people know what a Pikachu is and looks like. The Anime the fans demand wouldn't be profitable in the long run. If they introduced all the concepts once and never again, it would alienate new viewers, especially since the show has been running for close to 20 years now. Power creep would be a problem really fast, if the main character kept his team when travelling to a new region, it'd be like trading over your post-game team from the previous game when starting a new one.
That being said, I agree with this:
Can we please get new writers? Some who actually gives a s***? Ones who follows the story of the games, based filler on stuff in the games, when they debut or write stories around a Pokemon have their dex description and/or stats play a part (and save a Gym Leader's ace Pokemon to be debut in the Gym Leader battle). How about have the writers play the game and while doing so have them take notes of their Pokemon journey, if they're good writers they should have a saga worth of storylines and plots to tell.
Ash and co.
could do good stuff within the frames imposed by the needs of marketing. There could be better mini-story arcs, especially since there have to be so many padding episodes to fill in the time between important events. After all, they're stretching out the content of a region to last for several years - which at this rate averages out to more than 150 episodes per region (which basically comprise eight gyms and a short Pokémon League arc). They could drop the obligation to have an episode focusing on every single Pokémon out there, since that leaves very little time left to develop the main characters and their Pokémon.
As it stands, I guess the Anime fulfills its core goals well enough. It does what it has to, but nothing more. And that has earned it a reputation of being really dumb, and most fans of the franchise despise it. I've found ignoring it to be the best solution. It's not the show we want, it can't be the show we want, and it's written by (and for) people who have no understanding of the games. Might as well pretend it doesn't exist.