I would suspect the drow add just enough light to their underground cities to make the prevailing light "dim".
That way they can see fine, but its still a dark spooky eerie drow city to others. (The few humans that visit, lol)
As a DM, if you have a darkvision party that insists on doing all their dungeoneering without light sources, just throw some standard traps and trip-wires in the corridor. A tripwire requiring a DC 13 perception check to spot won't be noticed in dim light (ie what you get form darkvision in total darkness) until you have a passive perception of 18.
PCs should be making a choice — actually see what we're doing and not get killed by traps, hazards and other things that could care less how stealthy we are, or sneak around in the dark and not get noticed by the creatures that are looking for us.
I'm just about sick of Darkvision. Why is it that every single bloody race seems to have Darkvision now?
No, the level of darkvision was much better in 3E.Tradition. Heck, in the 1e MM, /everything/ had "Infravision," just be virtue of being listed in it.
Not being able to see in the dark is prettymuch a disability suffered by humans and some halflings in D&D.
It was one of many things that made non-/demi- humans highly desireable at low levels, only to be balance by their level limits, giving the game to humans at high level.