What you think PCS are doesn't match
what the ISU has up on its website*. If you look at them - not even all that carefully - you will also see that skating skills (and transitions) are not prerequisites for high marks on every other component.
Not officially prerequisites. But there are references within some of the criteria for the other components that rely on skating skills and can be used by judges (for good or for ill) to justify tying the marks for those components to the level of skating skill.
For Transitions it's more obvious anyway -- clearly the difficulty and the quality of the transitions rely on skill level.
For Performance and Execution, Carriage, Clarity, and Variety and Contrast criteria either rely on, or in the case of Carriage may contribute to, the "Balance" criterion which is the very first thing mentioned under Skating Skills
Carriage
Carriage is a trained inner strength of the body that makes possible ease of movement
from the center of the body. Alignment is the fluid change from one movement to the
next....
Clarity of movement
Clarity is characterized by the refined lines of the body and limbs, as well as the precise
execution of any movement.
Variety and contrast
Varied use of tempo, rhythm, force, size, level, movement shapes, angles, and, body
parts as well as the use of contrast.
Component training video on Balance:
https://www.youtube.com/watch?v=NzcS_HlgLKQ
Under Choreography, the Pattern and Ice Coverage criterion reflects skating skills (pattern is directly related to multidirectional skating; ice coverage is related to power and depth of edge).
Under Interpretation, the first criterion is Effortless Movement in Time to the Music. Some judges might put the emphasis on the Effortless Movement part of that phrase, whereas others might focus more on the In Time to the Music part.
At one extreme you might have some judges who are very technically oriented and aren't interested in, knowledgeable about, or sensitive to performing arts qualities at all. They would probably focus on the skating quality aspects of those later criteria in the areas I just noted and give little or even no attention to the more arts-oriented criteria.
At the other extreme would be fans who love dance, music, theatre, circus, etc., and know and care zippo about skating technique, who would be just as entertained by actors or dancers or acrobats performing to the music on the ice, wearing blades, but mostly doing movements that could just as easily be done on the floor in special or ordinary shoes or in bare feet.
Clearly almost all judges and almost all fans will fall somewhere between those two extremes. But which end they tend toward could be a matter of disagreement among judges as well as among fans.
There's lots of room for improvement in how to define these components so that everyone can be closer to the same page in understanding what each of them is supposed to measure.
