The new generation is going to be like this; it's diminishing returns, but not as we know it. On a technical front developers have never been better served, but on a creative front they're hemmed in by their own success. SSDs in consoles should genuinely drive a leap forward in game design, but I'm not convinced we'll see it. More and more studios are now cleaving to the tried and true approaches: from innovation to iteration, from iteration to reiteration, so that more and more of what we get is sequels, remakes and remasters, all of which share much of their design with their contemporaries.
And I reckon that's largely to do with success and standardisation that's happened across the industry: just take a look back at the controllers for the PlayStation, Sega Saturn and N64 - all wildly different with different aims and quirks. Now look at the Switch Pro, DualSense, Stadia and XBOX Series controller and the silhouette and layout is almost identical. Even when new gen exclusives do roll around, I'm not holding out hope of anything transformative, just prettier, slicker, more refined (or perhaps even more bloated) versions of what we already have.