Ah, the question that comes up over and over this time of year. Why are resorts closing when they have the deepest base of the season?
As others have noted, the simple answer is the lack of crowds to pay for operating the facilities. Once Spring Break is done, people stop skiing, even if conditions are amazing.
For a ski area, it sounds better to hint that they close for environmental reasons, but I have yet to hear the forest service definitely say "They have to close after the first week in April because xxx." for any resort. The forest service does have to sign off on opening and closing days, and if a resort wants to open earlier or stay open longer than the days already agreed upon, the forest service needs to approve, but I have yet to hear that request get denied.
Wolf Creek closes on the 6th. They got about a foot of snow down on Friday. On Saturday there was a day's worth of untracked skiing to be had everywhere you could look because nobody showed up Friday. Even Saturday only about 200 cars showed up, maybe 400 people skiing 1600 acres.
Sunday was a day that everybody gets a lift ticket for $38. Nobody showed up. I would unload at the top of the lift and look back to see empty chairs as far as the eye could see.
People stop skiing in the spring. If you want things to change, find a way to convince people to come out in the spring instead of skiing dirt on Thanksgiving.