The 911 was designed in the 1960s, the one displayed is from 1973. The reason the design is iconic is that the car is rear engined which gives it the unique characteristics of driving and style. It also allows for an aerodynamic profile while still having 4 seats. Having a horizontally opposed sir cooled engine also keeps both weight, cost and centre of gravity low, giving better handling, efficiency and mileage.

By the 1980s the design was quite dated but still popular because of the reputation of the car.

The reason pg probably picked the car was because the form followed the functions, it was designed rather than styled.