Techspot published an article that compared eight GPUs across six, high-end dies in NVIDIA's last four architectures: Fermi to Pascal. Average frame rates were listed across nine games, each measured at three resolutions:1366×768 (~720p HD), 1920×1080 (1080p FHD), and 2560×1600 (~1440p QHD).
The results are interesting. Comparing GP104 to GF100, mainstream Pascal is typically on the order of four times faster than big Fermi. Over that time, we've had three full generational leaps in fabrication technology, leading to over twice the number of transistors packed into a die that is almost half the size. It does, however, show that prices have remained relatively constant, except that the GTX 1080 is sort-of priced in the x80 Ti category despite the die size placing it in the non-Ti class. (They list the 1080 at $600, but you can't really find anything outside the $650-700 USD range).
It would be interesting to see this data set compared against AMD. It's informative for an NVIDIA-only article, though.