I can see your point, to a point, but...
Muscle coordination means something. You don't have to be athletic, but you do need some kind of muscle coordination.
@Tricia 's point above is right on. My first instructor told me that his biggest frustration was students
just like she described: no sports ever. Completely out of shape couch potatoes.
Agree that muscle coordination and other sports experience makes it easier to learn.
My easiest student ever in tele instruction was a national level competitive XC-skier, medical student, but a never-ever on downhill gear. I could tell her to flex the ankle more, don't break at the waist and tilt your pelvis a bit more forward and she would make the changes instantly. Actually put a fair bit of pressure onto me as a rookie instructor because I felt she had the muscle coordination, movement awareness and balance to just do what I said, so it was all on me to exactly describe the the changes she should make.
But I don't think aerobic fitness and strength in isolation is important for learning to ski.
For myself I have started to train for ski fitness many times and quit an equal number of times. I could go at it for months and be able to increase the number of repetitions on a weight exercise from say 4 to 10. But then when I stopped it would return to baseline in about the same time frame that it took to build the fitness. Similar for aerobic fitness. This year after months of hard training I improved my time up a hill on bike with 15 %. But now after a few months of inactivity I'am back where I started. IT'S NOT FAIR
. It will be hard to grow old in the age of GPS-tracking. Lets hope that it's a fad that passes...
I actually don't think any of the things I have done for ski fitness over the years has had any noticeable effect on my skiing.
One thing I like about getting better at skiing is that skill improvement is not as volatile as fitness improvement. Most of us can take a 6 months pause and then continue improving not that far from where we left of. I guess that is something we should appreciate as relative beginners since that effect will be smaller as we improve.