@EricWN
They don’t have because it would be killing the sales, be a engineering nightmare and it would be nightmare for support and brands when people lineup to whine how the image plane is off and they can’t get correctly focused photos.
Many of us has dreamed that one day we could have those sensor modules swapped. I would even accept that if it would be required to be done via the manufacturer service where they swap the sensor module away to new one, keep the old sensor and then re-check that sensor is correctly mounted.
But same time we would need to change CPU, battery etc.
A highly integrated computer for A/D conversion isn’t just so easy.
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.