The reason I ask the question. Before digital, the various manufacturers made their respective bodies and lenses while the film was made by someone totally unrelated to their company. The things that set one camera manufacturer apart from another was the build quality of their bodies, ie: ruggedness, sophistication and their lens construction, ie: build quality, optical quality.+10000000000000000000000000000000000000000000000000000
They all used the same "imaging device" if you will. It was called film. It could be made by one of several different manufacturers, Kodak, Agfa, Fuji, Ilford, etc., all with their own image characteristics. One film stock could be used to compare the quality of one lens vs another. One body vs another.
So why is it important that Canon even make its own imaging sensor? Nikon tried then decided not to. They gave up on the the sensor race. They didn't have the size company with the deep pockets Canon had. Now, Canon should just buy them from Sony like Nikon and let the sensor wars become the body and lens wars again. I don't think Canon has the deep pockets or research capabilities Sony has for the long haul.