Match racing AC72s is different from historical classes because of the very "forward" apparent wind angles.
In the old days, you could stay on top of your competition upwind, matching tack for tack, constantly leaving your competition in disturbed air. But not with AC72s. Your competition can be positioned directly downwind from you, and still be sailing in relatively clean air (not turbulent, but still possibly slightly "bent").
Similar dynamic on the downwind legs. Those boats reach downwind at approximately twice the true wind speed, so during a quick, well executed gybe, I suspect the boat can "breathe" undisturbed air from ahead, even if the competition is making a mess of the air right behind.
Footnote:
Though those big-budget AC72s can be considered a compromise compared to other (historic) match racing classes, there are still plenty of those classes available for sailors and spectators who seek a more "authentic" experience. The difference is that those classes aren't a big spectator and media sensation. Unfortunately, it's hard to have it both ways. Though I've been an avid sailor for most of my life, I wouldn't have bothered paying much attention to the America's Cup races if it weren't for those amazing, wildly stresses, high-tech boats.
Cheers,
James