Nice ideas you have there. Have you ever noticed the eroded "V" shape in the great step seen in older photos? I have wondered if the portcullis slabs were themselves counterweights that wore it down with use. Perhaps the portcullis slabs as counterweights operated the "pyramid machine" by moving the granite slabs (now wedged permanently at the entrance) and probably slabs that would seal and unseal the queens chamber pathway where those notches are.
In any case, the worn great step probably happened in conjunction with pyramid operations. The fact that it is worn means it was used over and over again.
All t he best,