That's a great, valid point... Still interesting to me that he unloaded almost all his vested shares. The media was sure to pick up on it and executives often buy back shares to signal confidence.
Maybe he was simply trying to balance his asset allocation. He's definitely not living off $40m, right? It always seems that Apple is sure to outperform, but maybe we'll look back on this as a genius move in a few years.
EDIT: Updated the title to richardburton's suggestion.