Honestly, this news isn't a complete surprise. With the success of the Nintendo Switch, and a probably premature announcement of a Switch entry to satiate hungry Pokémon fans, the death of Pokémon on the portable Nintendo 3DS was inevitable. Even if it's expected, it's still a bit sad.
On November 17th, Pokémon Ultra Sun and Ultra Moon, a sorta-sequel to the original games of last year, will be the series' swan song on the device. In the meantime, Pokémon lives on in its multiple mobile offerings. Eventually, the game will make its way to Switch too, but who knows how lushly made it will look—will it remain as bare 3D as the 3DS entries, or will it take the step into HD gaming? Only time will tell.
Game Freak confirmed the news to IGN in an interview today. "With Ultra Sun and Ultra Moon we’ve tried to eke that out more and really, really push the system to its absolute limits, and we’re now feeling that perhaps this is the maximum of what we can get out," Game Freak director Shigeru Ohmori told IGN. "So we’re really treating Ultra Sun and Ultra Moon as the culmination of our work with the 3DS system."
The game's director Kazumasa Iwao goes on to note that the team for Ultra Sun and Ultra Moon is comprised of only 80 people—half the staff of the 2016 games. While Ohmori didn't enlighten IGN with what the rest of Game Freak was working on, it's easy to assume that it's the debut Pokémon RPG for the Switch (and maybe even other projects as well). The dual games of Pokémon Ultra Sun and Ultra Moon will be out soon on Nintendo 3DS, on November 17th.