Without seeing the more specific data in that "report", we're merely speculating on the reported "drop" of participation. In all likelihood, it could be women in their 40' and 50's has been dropping out of skiing all along and last year was just a bit bigger than before.That doesn't explain gender or age though. I know a lot of the people we used to see regularly skiing would say they had just "given up" for a while these past two seasons. Even my husband was pretty unmotivated this year, which was a first.
Don't forget, the last of the baby boomers had just gone past 50. Basically, the largest population group had just aged past the age range in question! That alone, may account for the entire "drop" altogether!