Today marks the 20th anniversary of the release of Pokémon Gold & Silver in Japan, which are still considered by many to the best games in the series and were the last time Game Freak took a risk and tried something ambitious with the Pokémon world.
Pokémon Gold & Silver were already in development in 1997 when the games were shown at the Space World '97 event. The games would later be overhauled from the ground up and released in 1999. It wasn't until 2018 when the Space World demo leaked online that the extent of the changes was first realized. Pokémon Gold & Silver were almost entirely different games, with a number of different Pokémon and a setting that encompassed the entirety of Japan. It was originally planned for Pokémon Gold & Silver to be the final entries in the series, which is why Game Freak had wanted to end on a high note.
One of the most amazing aspects of Pokémon Gold & Silver was the fact that they managed to fit two entire regions into each game. Once the player had conquered the eight Johto Gyms and defeated the Elite Four, they could travel to Kanto from Pokémon Red & Blue and challenge the original Gym Leaders and even the protagonist of the first game. The addition of Kanto was possible due to the assistance of former Nintendo president Satoru Iwata, who designed a program that allowed the developers to squeeze all of the necessary data into a Game Boy cartridge.
The fact that Pokémon Gold & Silver were once planned to be the final games in the series is why they contained so much content in comparison to every other entry since. The return of Kanto (as bare as it was) and the climactic battle against Red stand out as some of the best moments in the series. The success of the Pokémon franchise is what would doom it to mediocrity, as the rest of the series has fallen prey to rehashing the same concept over and over again. Each new generation of Pokémon games comes with its own shiny coat of paint, some new features, and a few new Pokémon, but the games have never pushed themselves too hard in terms of story or content because they don't need to.
Pokémon Gold & Silver marked the end of the era when Pokémon could leave its comfort zone and try something different. This isn't to say that the rest of the Pokémon series hasn't been fun or had awesome moments of their own, but there is always a feeling that it never really matters and that the status quo will always be returned to in the next games.
The cyclical nature of Pokémon has prevented it from reaching its full potential and the possible end of the franchise is what prompted the developers to try to end on a high note with Pokémon Gold & Silver. The final battle with Red marked the end of an era, with Pokémon Ruby & Sapphire starting the trend of a Pokémon journey that never goes anywhere. Pokémon Gold & Silver offered fans the ending that they would never find in the series again.