A high proportion of lens patents never become lenses. The designs are patented in case they are wanted at some time in the future, and as protection against patent trolls.
The DL cameras were high-end non-ILCs, so it is not hard to imagine a successor being non-ILC. It is hard to see Nikon giving it a single focal length lens instead of a zoom like the DL, however. I would be interested in a compact APS-C camera with a fixed 35mm lens, but I doubt there is a big market.
When a camera is for documentation a fixed, known focal length and a curved sensor is ideal. A lot of that happens in health care, eg - pre and post-surgical documentation by plastic surgeons and dentists, lesion surveillance by dermatologists, telemedicine etc. A fixed 35mm lens with a curved sensor might be for a niche "documentation" camera.