I don't think this is true for Massanutten though, it's got skiing in the winter, then has mountain bike trails in the warmer months, as well as hiking, go carts, indoor and outdoor water park, bussed day trips to a river for kayking and tubing, arcades, pools, hot tubs, steam room, sauna, multiple restaurants, arts and wine areas and events, and it's so big that's probably leaving a bunch out. Literally stuff to do every week of the year. Also 45 minutes from a bunch of caverns, a university town with various restaurants and shopping options. I really do think it's a 4 season resort.
Honestly I think the main issue is it's almost too big and just has massive capacity, and while there's a lot to do there I figure it'd need something like another Disney park to fill all those units they have across what, 6k acres? If it had about 1/2 the units, it'd be packed much of the time. But for those in the know, it's very often available cheap in Extra Vacations and Last Calls so owning there would only make sense if you could get a really good trading unit I think. IDK, they might have some RCI Points units that are that - I vaguely remember that. But that's for TUGers.