And if these 50-series specs are anything to go by, they made a good call in doing so. All the big improvements are coming in mid-range cards, where AMD, nVidia, and Intel(!) are trading blows.
If the only way to get better raw frames in modern GPUs is to basically keep shoveling power into them like an old Pentium 4, then that’s not exactly an enticing or profitable space to be in. Best leave that to nVidia and focus your efforts on a competitive segment where cost and efficiency are more important.