Someone said it above, but I think this is just the result of Pokemon not being steered by a passionate, ambitious group (or individual). At this point, everyone who worked on Red/Green must have retired, moved on, or been promoted to a hands-off role, no?
For Gen 1 it was Tajiri and Sugimori creating basically doujinsoft with some pals based on some manga they had kicked around, passion in an environment like that is naturally going to bloom. It was Tajiri's strong vision for what the game's world would be and would not be that set the tone, and even for the media blitz that followed, the partner companies employed equally passionate people: think Shudo helming the anime, or even Ishihara and the TCG.
After Masuda took over, the franchise definitely changed, but he was an uncompromising director early on, barely completing RS and DP in time to ship because his teams wanted so many features, and just couldn't help themselves from trying things. He had a real vision for Pokemon as a setting, and not just as a franchise, and even if you disliked his vision, it's inarguable that the games he made pushed the series forward, and you could feel that they were stories written by people who believed in them. The trove of lore from the Terraleak is proof enough of this passion. And I think Masuda's passion rubbed off on other teams, think about Emerald and HGSS also going out of their way to stuff new things in. Ohmori, for all his faults and how bad his games are, also seemed to be affected by this early on. I don't think he's a great director, but I also don't think the major failures of Switch Pokemon are entirely on him.
But other than that, who's left? Masuda was pushed aside to rot with Tajiri, Sugimori essentially does nothing, Ishihara never had the same passion for Pokemon the world and remains, as ever, a salesman. Turner? Forced out.
The truth is, unless something happens that forces a shakeup, Pokemon will be bland, safe, and sterile, until someone steps up.
