From what I've read, a problem with petro textiles, early ones or later developed, is they break down to small and nano plastic particles that are pervading the environment and interfere with endocrine system/glandular functions. They are already a huge problem, and many of them contain fluoro compounds at this point (literally thousands of different synthetic fluor compounds, so far three to four of them studied).
Some people do ski in non plastic gear.
Check out one of
@Dan Egan's sponsors
https://www.alpsandmeters.com/
Their stuff is really well made. A bit heavy, but well made. Wool. Waxed Cotton...you name it.
The problem with most of this company's outer layer clothing is that the natural materials are on the outside (for looks or appearance?) to face the elements; and the "membrane" synthetics are hidden on the inside, closest to the body. This is the reverse of what would be most practical for skiing or mountaineering, to me, since it's the synthetics that can most often be wind and water repellent in the most lightweight and efficient manner.
The synthetic "membranes" of the above company (just thin synthetics?) are a key part of seemingly all of their outer layer products: but their synthetics are on the inside, waxed canvas/cotton on the outside. This makes little sense, to me - except for show.
Since I started skiing in the early fifties, I remember and used many of the pre-synthetic materials. (And synthetics came way before leather boots were discarded, and before those boots had buckles.) The wool was very itchy then, no smart (merino) wool, for most of us.
In these early setups, and my own now still, the natural materials are/were better (for me) on the inside, nearest the body, and the synthetics, which are best for wind and water repellency, are/were better on the outside, where they can/could do what they do best (instead of some outer heavy waxed canvas - heavy
and bulky - or some other supposedly natural material that may be heavily chemical-treated or otherwise coated (wax or oil) to make it truly able to repel the elements).