> Let's reformulate the question: Why not keep the same enclosure, the same lens assembly, the same mechanical parts and simply swap the 2MP sensor for a 20MP s

> Let's reformulate the question: Why not keep the same enclosure, the same lens assembly, the same mechanical parts and simply swap the 2MP sensor for a 20MP sensor? You can't "simply" swap the sensor. What about the processor behind it, that interpolates the sensor data and produces a viewable image? Then you need more power for both of those units, and if you're moving to a 20MP sensor, probably size too.