Even that isn't enough to be a good defense. (Though you're right that currently this is probably the most gaping hole in our current ID procedures.) Even if IDs were totally unforgeable, and ID checkers had a perfect track record at identifying fake IDs, there is still the problem that we don't know who the terrorists are. It doesn't help to know that the flier in front of me is called Bartholomew Greensbriar; what I really want to know is whether B.G. is going to commit an act of terrorism on this flight, and knowing his name doesn't help me answer that question.

People who think that photo ID solves an aviation security problem either don't understand photo ID, or don't understand aviation security.