The trick is to decouple the dorsiflexion of the ankle from the inward rotation of the leg. She keeps her outside knee in while sliding her foot forward. Where the natural tendency is to let the outside leg turn outward as the foot slides forward and thus reducing knee angulation, the best skiers can keep the outside leg rotated inward while sliding the foot forward. In other words they control the skis edge and fore aft pressure independently.
First dorsiflexion is a very weak movement that by itself has almost no influence on knee angulation, fore/aft balance or anything else to do with skiing except possibly helping to hold the ankle flexed. However, if the hampstring is not activated and the foot pull back is not used to lever the hips back to a forward position relative to the boots dorsiflexion is useless. So there are many other things that need to happen before dorsiflexion can even be part of the discussion. In addition, dorsiflexion has absolutely nothing to do with knee drive, which Ron thinks are linked.
Where the natural tendency is to let the outside leg turn outward as the foot slides forward
I don’t get this at all, that’s not a natural reaction. If it were every WC skier would have the knee turning outward after the gate is passed, as that is when the pressure comes from more forward on the ski, to more middle, to back on the ski. This is usually achieved by leg flexion, not lack of dorsiflexion.
Ron may be reading the anatomy books, but he doesn’t understand practical applications. Even by Ron’s or PSIA standards of confusion, this is overboard. I think that every year Ron has to invent something new about technique to keep an audience; so now he is throwing out these absurd notions. If the hip is inside and the ski is pressured, the ski can move forward naturally if the hamstring is relaxed or if pressure is transferred toward the heel of the foot. There is no natural tendency here for the leg to turn outward, if anything, it is locked onto the edge and the ski will rail away.