These men are about the same age and same race, and most have the same equipment.  Same hairstyle, same bowtie, same rimless glasses, same cigar.  Despite the standardization, the artist managed to capture a unique quality in each man.
A less obvious example:
 
These cars are about the same age and the same type, and have the same equipment.  Separate headlights, vertical radiator, open fenders, sedan body.  Despite the standardization, the car in the foreground INSTANTLY shouts HUDSON!  The artist captured the essence of Hudsonness with a few minimal lines. 
Car-icature. 
   
    
The current icon shows Polistra using a Personal Equation Machine.