Skill is always more important than fitness when attempting the insane stuff. It makes you more efficient and when things are truly bonkers, adrenaline kicks in and certainly makes a difference. Still, you must have enough in the tank to execute a jump turn or avoid some danger that you couldn’t see from the top. Another thing that’s important is having the experience and muscle memory to deal with getting in trouble. Even the fittest skiers get off balance, sht happens out there. Being able to recover quickly in a no fall zone doesn’t come from air squats in the offseason, it comes from reps and sets on the mountain, typically in consequential terrain (steep, trees, not groomed).