My guess:
If you start with the idea that you want the economic activity in the Adks and Cats, then the money spent on ski areas is probably coming back in taxes etc. If the SKI3 areas were gone, many more would be on unemployment year round and many would probably move away.
The Adks and Cats are not the same.
If Belle was to go, much, but certainly not all, of the activity would get shifted to Hunter, Windham and Plattekill. Gore and WF are different, you'd lose that economic base.
If (somehow, yea yea I know just go with it) the areas were to become truly private, things would change in other ways. Slopeside lodging, more steady and reasoned capex investment. Yadi yada.
For my own selfish reasons I like it the way it is in the Adks. Slow progress, old schoolish, no slopeside, pretty uncrowded really.