They cannot detect pavement problems such as ruts, failures or slab breakage, and nor do they detect electrical/lighting problems. The report makes it clear that at JNB they missed the unserviceable sign and the many non-functioning taxiway lights
Remote monitoring of physical surfaces is difficult, but checking individual lights is within the compass of existing technology. If my car can check the functioning of each of its light bulbs, or LEDs, every time I swich on the ignition, surely a similar system can be devised for all functional lights at an airport.
A simple-minded scheme based on current drawn by a long string of lights may not be sufficiently sensitive, but including sufficient intelligence at the socket, with reporting back along the ower cables, should not cost more than a few pence per light. In total, less than a superannuable B747.
Too late for this particular horse, but such a scheme might be an effective bolt on future stable doors. If it worked, of course, we would never knoe because there would be no unknown missing lights to lead flight crew astray.