Another aspect of selecting chips for space duty is radiation. Spacecraft that venture beyond low earth orbit are subjected to much higher levels of radiation which cause all sorts of problems. This limits the use of many high performance IC's.
Notice the order in which the specs of the cameras are given by NASA here:
Location on the rover
Mass (which is always critical on a space probe)
Power (energy consumption)
Data return (the amount of data generated by the device)
Function obviously includes an expectation of long term reliability. Mass, energy ...
There is a very long lead time between procuring equipment (sensor in this case) and actually using it (on Mars).
It has to be obtained and tested against extreme reliability parameters of cold, heat, radiation, vacuum, vibration. Then it can be years before it actually flies. A newer sensor cannot be trusted as a substitute without undergoing all of the ...