Since you're looking at the idea from a CM Trajectory perspective I thought I'd modify your original drawing with some info that I think is a teeny bit more accurate for the sake of discussion.
I've drawn a red curve over your original CM path. This curve depicts a more likely CM path based on the (required) minimal pressure necessary for skis to actually 'carve' out of the old turn and into the new turn (I'm assuming no 'Air Pivot' nor 'Air Carve' here).
Even when the skier isn't deliberately supporting their CM firmly against the skis there must be at least some pressure
on the skis to keep the edges pressed against the surface. With an obligatory Equal and Opposite requirement we need that minimal pressuring-force to come from somewhere. I think it comes from "The CM" in a gross sense, but more accurately - from the Mass in components of the lower leg and ski gear.
As I see it the skier's CM might only be (say) 97% launched - with the remaining 3% resting lightly on the skis to keep them pressured just enough to carve the very large radius depicted at that phase of the Sine Wave ski track you've drawn. This tiny pinning-pressure can be created by launching our CM slightly
more down-the-hill rather than "straight" at our desired re-engagement destination.
Via flexion/retraction the skier's CM can be "greatly released" (but not entirely) from the old turn but still be gently guided toward the point of actual edge-neutral. This 'gentle guidance' of the CM provides the light pressure necessary for keeping the ski-edges pinned during the float phase.
As the Skier reaches actual edge-neutral (flat to the sloped surface) no directionally-redirecting force is needed and the skier's CM very briefly travels 'straight' (ignoring ballistic path implications).
The moment the skis roll far enough onto the new edges to again warrant some pinning-pressure the CM begins it's new turn also - due to the reaction force of creating that slight carve. It happens so imperceptibly that we generally don't notice it. Still, if those edges are tipped, engaged and pushing against the snow (even lightly) then something must be Equally and Oppositely reacting somewhere.
In the interest of Full Disclosure ... In the text above I used "The CM" as my reference point for the necessary Mass to work from and that's not strictly true
In the case of a multi-segmented skier each body-part has its own Mass. The lower-leg, feet, boots, bindings and skis might
have enough Mass themselves to accomplish the pressuring job on their own. A highly skilled skier with a deft sense of 'Touch' might
well exclude 99.9% of their Mass above the knee from the equation, though I'm not sure how this could be proven. Considering the muscle tension present in such active turns I'm pretty sure most skiers (including those highly skilled) have much more than just lower-body components involved in pressuring the skis in the moments of interest.
Further, any effort the skier makes to extend their legs to enhance surface contact creates an even larger reaction driving the CM along an even tighter radius curve into the new turn.