Just a Bill wrote:
The fact that we never see anybody waiting for a cab
Not so. There is at least one time that I can remember and it is from "The Naked Time". They just took crazy Sulu from the bridge and twenty or so seconds later Kirk attempts to take the turbolift and there is none waiting for him. He has Uhura to "clear that tube" and finally after a little more time goes by the turbolift door opens.