That's just how patents work. And not just for lenses. Any invention can be patented in this way and any rival will need to have a variation in the design, otherwise, they're infringing on that patent.
josephallenkeys
joined 11 months ago
One major aspect is autofocus and the motor systems needed to shift the large f-stop pieces of glass within the same housing whilst also offering silent motors, weather sealing, electronic control/communication and overall durability.
Historically and technically, primes are very simple designs, but, earlier designs could cut corners due to the formats they were designed for. I.e. b&w, 35mm, etc. These formats were nowhere near as detailed as digital images and so new elements are needed to refine the quality.
They also have a lot of patents taken up. The Leica and Zeiss patents for Summilux and Plannar, etc are very old. So rival designs often needed to take the long route to the same result.
But it all together and you have that behemoth of a Nikkor!
You can print all your images out and let them go from a high window on a windy day. It's just as, if not more effective than throwing your images into the digital noise of any social media.
(Please use eco friendly paper.)