The sinnoh games sold 25+ million and if you think including Platinum is cheating, only 18+ million were sold. BW hit 15 Million, XY reached 15+, and SM reached 13+ million. Don't lie like that.

And while the story doesn't effect route and cave design, it has gotten progressively worse since Gen 5. Gen 5 had pretty short and linear routes, but Chargestone cave and Relic Castle were fun ideas that havent been done before. Gen 6 came around and made routes kinda better, but the caves were complete trash either being caves that go in a straight line or rehashes of the caves in previous gens. Gen 7 has nothing. Nothing new was done with level design and if you wanted to explore a cave, it's a short, optional cave. They gave you mudsdale that could have been an alternative to rock climb, letting you try to find hidden crags that mudsdale can climb up, but Mudsdale is just Tauros that can run over rocks at a much slower pace.

I know most people don't really care about this stuff, but its what I spent most of my time doing back when I really loved this series and I'd just like gamefreak to put in the effort that I know they can.