Well, yeah.... I think you take my point. The system is set up to work in a certain way. It doesn't depend on the Station Agent doing a runway sweep, otherwise things could get pretty hectic. For one thing, with no Tower, how is he going to be cleared to move? You just end up piling layer upon layer that way, trying to slap a patch on a system that broke down due to a single-point failure mode, a sleeping controller locked away in the tower with no way even to find out what had happened to him.
People do occasionally have heart attacks or strokes, too, when I would be curious to know what the FAA's Plan A is for that scenario.