Nikon needs a new D3/D700-tier body to get back into the game. Right now their bodies are just 'competitive' with Canon and Sony FF bodies... back when the D3 sensor came out, it put the final nail in the coffin for most analog film shooters.
Now phones have eaten both compact cameras and hobbyist DSLR markets. Prosumer and professional DSLRs/ILCs are a niche market and Nikon is becoming a niche company.
If your hobby is shooting sports, wildlife or stars (big balls of gas), buy an ILC. If all you need is a travel camera, an iPhone is a damn good one and it's smart enough to beat 9 out of 10 humans fiddling arround in Lightroom.
Nikon, if it were to survive, would need to move into new markets. dSLRs are dying, but imaging is exploding. Nikon and Canon ran into the innovator's dilemma: they didn't want to eat into their core market, so they released crippled products like the Nikon 1 or Canon M-mount. By the time they got into the game, their market was collapsing, they lost a lot of credibility, and Sony had a huge lead. It's probably too late, but we'll see.
Drones, industrial, teleconferencing, and hundreds of other markets are popping up, but Canon and Nikon are conspicuously absent.