Just moments ago, I managed to turn a photo of a person into a short clip of them dancing, in half-decent quality, fully locally, on a mid-range gaming GPU (RTX 4070 Ti, 12GB VRAM). I almost run out of RAM (32GB), but it worked, worked well, and took only couple of minutes.

Half a year ago, that was sort of possible for some genius really bent on making it happen. A year ago, that was unthinkable. Today, it's a matter of drag&dropping a workflow to a fresh ComfyUI install and downloading a couple dozen GB of img2vid models.

The returns on R&D are not diminishing, the progress is just not happening everywhere evenly and at the same time.

Not only did the iPhone 9 never exist, the iPhone X was a huge paradigm shift in design and capabilities. That was the phone that introduced edge-to-edge OLED screens to the iPhone line, as well as the IR camera that enabled FaceID and the first generation of Portrait mode. I know it well since it also introduced the ability for developers to build facial motion capture apps that would’ve previously required expensive pro hardware and allowed people like me to build live facial motion capture effects for theatre.

Sorry to dunk so hard, but your example of technology stagnating is actually an example of breakthrough technological innovation deep into a product’s lifecycle: the very thing you were trying to say doesn’t happen.

At the risk of unbearable pedantry, there's never been an iPhone 9. (There was never a 2 either; there was kind of a 3, although it was really called the 3G.)