All in all, I agree with your assessments. Its good to note that what you are trying to do is read the amount of light hitting the target. This could always be

All in all, I agree with your assessments. Its good to note that what you are trying to do is read the amount of light hitting the target. This could always be done with a ambient light meter placed in front of your subject (Studio). The issue was the convenience of seeing it through the camera. The first automatic in camera meters were limited to high-key or low-key and tried to just make the picture's average lighting match the 18% grey card, a portion of it (center weighted or spot). Highly colored subjects could throw this off as the meters weren't always linear to all wavelengths. As technology advanced, matrix meters used multiple points to try and guess tricky lighting conditions. As more elements to the matrix were added, identifying where the subject became possible. However, they all are just trying to guess at the level of light hitting the subject of the photograph.