Well, it has aged, though for some extremely unfair reason, antiquated male fashion feels slightly less ridiculous than outmoded ladies' fashion. Or perhaps I'm just too ignorant in / bored stiff with suits to spot the difference.
At any rate, costumes, dialogues and music are clearly outdated; but still!
Still, this is a masterpiece.
In my not always so humble opinion, 'Duel' is probably to this day one of Spielberg's top five.