Nikon made the 35mm SLR cameras, the first of their kind. Interchangeable lens. Prior it had been rangefinders by Leica and Zeiss. Nikon is an optical company as their primary focus, so they have imaging products, medical equipment, binoculars and etc.
While Nikon was the consumer brand of photography, they were very late into autofocus, which is when Canon came into the picture. Likewise, with digital cameras, Nikon was more dated in coming out. Since the D300, they've been making gems.
They make great SLR's for photographs. Video is lacking. Telephoto lens were their forte, having the very best. And their pro-grade autofocus is why so many sports photographers used to shoot with Nikon. No consumers do not have this crisp auto-focus.
One of the things people have stuck to Nikon is because they've stuck to their F-Mount throughout history. Pro cameras can generally adopt any lens made throughout their long history. They have a complete lens collection for full frame, FX. For cropped sensors, DX they're lacking, although I figure they're stopped or stopping production for DX.
They're a company of engineers, which don't typically have a social outreach or marketing division. Other companies like Sony and Panasonic (both are conglomerate huge) will have teams survey the experts for revisions and they'll implement them quickly. Nikon, no.
Nikon for the longest time has coasted on their ability to make good camera bodies. But since Sony has changed from a massive electronics failing conglomerate to a specialized leaner 6 sections (Playstation, Cameras, Finance, Semiconductors, Batteries, Entertainment). Current Nikon senors were produced by Sony, and there's some sense, they're contracting Sony for their current top of the line sensors.
I don't think Nikon is going to survive. They're been almost routine in introducing a number of lenses and bodies per year. Last year was an anomaly, and this year is very slow as well. The company is dying.