Not to go off topic too much, but leaves don’t die from lack of light. Leaves get chlorosis because they lack proper nutrition to maintain replacement of chlorophyll pigment as this pigment decays.
Anytime a photon (light) make contact with a leaf, decay of the chlorophyll pigments happens. This decay is a good thing because it means that the leaf is manufacturing photosynthate (plant food) to pass to other areas of the plant based on higher “sink strengths”.
The inner leaves are not growing anymore and yellowing, because they lack “sink strength”. This just means that the plant has determined more important areas of the plant to sent it to. “Sink strength” is the plants way of determining where to send it’s available nutrients. Since there isnt any nutrients being sent to the inner leaves, chlorosis occurs, cell structure suffers, and eventually the leaf drops off.