The problem is pretty simple; the stock of mountain resort towns has not kept up to satisfy demand. Imagine 15 or 20 years ago, a trip to a somewhat remote mountain town had a lot of inconveniences like bad internet, unpredictable weather/travel conditions, etc. In the current year, it's very easy to book an entire trip to Vail/Tahoe in 30 minutes. The amenities and infrastructure are decent making it a viable place…
It's not just the cost--the market has changed. Hotels are like cable companies or pre-iTunes record labels. People prefer renting a private, detached, house rather than a bunch of hotel rooms because it's a nicer experience having a shared space with your whole group away from strangers.
Families can dry their ski clothes by the fire while hanging out in a living room while grandma makes her famous gnocchi for dinner. Then they can go to bed at a reasonable hour. Meanwhile, a group of friends can get drunk in another rental until the sun rises. These two incompatible personas don't have to interfere with one another[0]
Okay, yes, there are hotels with cabins. These are still too close together and not big enough to accommodate what the market wants out of a vacation experience. It's the difference between five friends paying $4k for business class seats versus spending $20k to charter a private jet and splitting it.
[0] We're assuming the friends stay indoors and aren't a neighborhood nuisance--certainly not always the case, but sometimes people get drunk responsibly.