Every time when a new generation comes everyone measures how big of a jump it is only by graphics , nobody cares about the mechanics , level design , complexity and interactivity of the world/npcs , AI , better/more realistic destructible environment
I think this is because it kinda has to be.
AAA games are so inflated with costs because of ever expanding visuals and scope and hence production value (lots of actors, marketing, middleware and generally very expensive development utilities). They need to sell millions of copies and therefore have to attract the broadest audience as possible and for that need to be looking exceptional and stunning on pictures and footage, and they need to be accessible. So, games get, mechanically, """streamlined""" and usually less complex and generally easier to pick up. Innovation stays often behind. Just look at the typical big sellers and how exchangeable they are in reality, often, a bit hyperbolic, only offering new tapestry in the same old house.
Complexity of AI and interactivity? Funny enough that this was better in Assassin's Creed Unity than in any other AC come after. AI in Cyberpunk is a joke. AI in GTA V is often worse than in GTA IV as many videos on YouTube compared. Remarkable milestones are severely lacking.
Environmental destruction? Almost non-existent and very minimal when I look at The Last of Us 2 or even shooting-focused games like Gears 5 and many others. Destruction as in FEAR (over a decade ago released) should be the bare minimum standard for today and many games, even AAA, fail to achieve that. Control being an exceptional example in how good it could be (although it is a little exaggerated there of course).
NPCs in games like Gothic and Risen (games one and two decades old) felt more alive than in many modern, high budget games, because they now seem to care only about size and scope, because on paper and on videos and screenshots it looks amazing. I mean, look at Cyberpunk and you can't deny it looks amazing. But I doubt someone feels truly belonging to the world with that little NPC interaction and often broken AI.
Mechanically, many games are getting broader, not deeper. Perks and crafting and XP bars seem to be the standard in so many games these days, but real intricate, innovative and next gen mechanics are left on the track.
And looking at Horizon Forbidden West there's little next gen about it except for the visuals. Aloy can now dive and explore underwater levels, which is new in Horizon but far from new in the genre and in games. Movement and combat is more refined than next gen. Visuals are simply one of the top sellers because it's the first you see. Everyone I talked to and showed it says "wow this looks amazing! I'd try it out", even those people not playing at all.
Ironically, if you're looking for "next gen" gameplay you probably have to look at the indie branch of video games.