Why are ski ponchos impossible to find?

On days where it’s legit raining on the hill, Gore-Tex only does so much. I managed to get my hands on a proper poncho this year and it’s been super key and saved a few ski days for me this year. But they are extremely hard to find, even on the internet there’s only a few options.

Why is this? If there’s any region where these are useful it’s the “PNW”. Obviously you can use the cheap disposable ones (or a garbage bag) but nice to have a proper one. All the ski clubs and mountain employees seem to have them but finding on at a shop is next to impossible.