The only way I see that happening is Nintendo lending development resources to achieve that. Game Freak has been content with business as usual, even going as far as reusing assets from an outdated system like the 3DS. They seem resistant to the longer, more complex development cycles required for modern gaming and lack expertise in creating those types of experiences.
That said, I still hold out hope for a true evolution of Pokémon—one that fully embraces an open-world design. When you look at how other franchises have exploded in sales after reimagining their gameplay—Zelda jumping from a steady 5–10 million per entry to 30+ million, or 3D Mario making a similar leap—Pokémon's growth has been relatively stagnant in comparison.
In my mind, a bold, fully realized Pokémon game has the potential to rival Grand Theft Auto in scale, easily becoming a 50-million-plus seller. The franchise is that massive. And yet, even with lackluster visuals, poor performance, and restrictive, unimaginative gameplay, Pokémon games still push 25 million copies without breaking a sweat. The fact that Game Freak doesn't seem to recognize or capitalize on this unrealized potential is a real shame, and they stick to their legacy games that for many non-hardcore Pokemon fans like myself is not appealing.