The original writer for the Pokémon anime, Takeshi Shudo, had a plan to end the series over twenty years ago, but it was so dark that it had to be scrapped. As lighthearted as Pokémon may be, it has dealt with darker themes at times, especially in the early years. Shudo’s original Pokémon ending for the series would have taken that to its peak, and that’s a large part of why it ended up being scrapped.
Takeshi Shudo was the original head writer for the Pokémon anime from 1997 to 2002. Shudo was in charge of the first three movies and the anime through most of the original Pokémon series, and he was even responsible for creating the Pokémon Lugia — although he did protest Lugia being added to the games. Shudo died in 2010 from a subarachnoid hemorrhage, and to this day, he’s still revered as one of the biggest contributors to the early years of Pokémon.
Takeshi Shudo was one of the main driving forces behind the Pokémon anime in its early years, and he even came up with his own ending for the series at one point. In one of Shudo’s final blog posts before his death, he wrote that he had envisioned a fourth Pokémon movie that would have had all Pokémon realize that they’re being treated like slaves and rebel against humanity, with Ash Ketchum's Pikachu leading the rebellion. Shudo abandoned the idea because it ultimately went against the rules of Pokémon (via LavaCutContent) - and that’s a good thing, because an ending like that would have been far too dark a final note for Pokémon, and would have done long-term damage to the overall franchise.
How Takeshi Shudo’s Pokémon Ending Would Have Changed The Franchise
The biggest change that Takeshi Shudo’s original ending would have brought to Pokémon was that it would have a defined end point, instead of the series continuously following Ash in new regions. Pokémon Gold and Pokémon Silver being delayed had caused Shudo and other people involved in the franchise to grow anxious over its future, with Shudo, himself, thinking that the franchise would end within a few years. Shudo also felt that the Pokémon anime had gotten into a rut at that point, so his ending would have served as a means of giving the series a definitive ending that it couldn’t walk back from. Shudo’s ending would have completely changed the status quo by breaking one of the core themes of the series, so it makes sense that it would have been the kind of thing to completely put an end to Pokémon.
Pokémon’s original ending gives an interesting idea of where the series could have ended up, but it wasn’t something that would have worked for the series. The reveal that humans and Pokémon actually can’t be friends would have broken the series to the point that it couldn’t continue, which was likely Takeshi Shudo’s intention when he conceived it, but even for a finale, Shudo’s plan would have been far too dark to work for the Pokémon anime. There’s been a lot of talk about at least the anime coming to a close for years, but even back in the early days, an ending that completely broke the series like Shudo’s would have been far too dark a note to end on for the otherwise relatively lighthearted Pokémon show.