It seems to be a general problem, not only Nikon: 5D3 also had a light leak, Fuji X-T1, leica released v1.0 firmware after the camera was shipped … for T if i remember correctly, a lot of shutter vibration in a lot of cameras (olympus, sony) …
So it is not a QC problem only, it’s probably more complex, and it is more about the time that is spend today in a generation: engineering & testing. They all should have a break, and slow down the pace a bit to allow for their teams to do the job properly. But marketing is marketing, and it has always been more important than… everything.
Started out doing photography at the age of 6 using an uncle's old 1940 kodak brownie box camera. At 15 years of age, I decided to buy my very own 1975 Praktica SLR camera. I now shoot with a Nikon D850. I do unpaid TFP and commercial paid work.