One other theory might be that a pharaoh might have remained impressed enough with the previous pharaoh after his death to dedicate his efforts to perpetuating that one's influence. If the following pharaoh still 'heard' the voice of the previous one as god, he might have felt called to serve him. Our modern understanding of ego and self interest might have been as weak as their apprehension of their own existence as a 'self'.*
*Basically a notion lifted from Julian Jaynes' The Origin of Consciousness in the Breakdown of the Bicameral Mind.
*Basically a notion lifted from Julian Jaynes' The Origin of Consciousness in the Breakdown of the Bicameral Mind.