Not necessarily. I know several people who have worked for MUCH larger and more respected agencies than A/M in other cities (even countries). The A/M culture is unique to A/M, and is directly created by its leadership.

They act like they are much more important to the world of advertising than they actually are, and their strange, draconian office culture is out of step with how the big, reputable creative shops do business today. It's an anachronism fueled by political muscle.