It would be very unusual to find such a person. These three drills cover 4 of the five fundamentals: fore/aft pressure control, foot to foot pressure control with direction of pressure to the outside ski, rotation, and edging. The one missing fundamental is pressure regulation. But if someone has ownership of these four fundamentals and still has issues, I think it is time to move to another realm. Weems Westfeldt introduced something called the Sports Diamond in his book "Brilliant Skiing Everyday." The four corners of the diamond are:
1. Power describes the relationship between technique, movements, physical forces, your body, and your equipment.
2. Purpose is about intention, strategies and goals for manipulating the snow and controlling your direction.
3. Touch is about the senses, emotions, connections, rhythm, flow, timing, finesse, and intensity.
4. Will is about choosing, preparing, moving, doing, balancing, centering, managing anxiety and commitment to action.
Technique, which the drills above focus upon, is in the Power realm. A student with mastery of the drills but who still has trouble putting it all together probably needs to focus on any of the other three elements. All four of these involve skiing, but the focus would need to be redirected away from technique and toward something else, depending on what was seen to be the limiting factor and where the student is at the time of the encounter.
Weem's suggestion is a bit more specific -- if Power (or any of the other three) isn't working, go somewhere else in the diamond and work on that.
Mike