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.
If the 911 turned out to look shit or be unfashionable, they would have changed the styling/stopped making it completely, like most cars from the 70s.
On the other hand, maybe it is still fashionable because they still make it? After all, generally what expert designers say is fashionable, is fashionable.
On the gripping hand, so? Maybe the turnover of style in a niche (sportscar vs mass-market) is slower (as you would expect given fast fashion and volume of play). That does not mean that niche is any better designed, only that bad design takes longer to be recognised and/or fashion tastes change slower.
And then I read "It's so obviously superior to the Cadillac that a child could tell it's better" and decided that either he's bullshitting or my design sense is non-existent.