Sun Valley does have some of these perks that are associated with a more upscale place--nice day lodges, great food, a lack of lift lines, lifties that handle your skis on the gondola, little amenities like free cubbies to store your stuff, nice bathrooms, good customer service, a gift shop/boutique that makes me want to buy things; bartenders that know what they are doing. But you can stay in a number of hotels there for ~$150/night; you can eat at the older lodge on top for relatively little; you can bring your own lunch and they won't bar you from eating in a lodge or stick you in a gross basement, and they let you have hot water for free; you don't have to buy a hand painted mug for $34 (it's so cute, I couldn't resist); in other words, it doesn't have to cost you $$$$. Or you can go for it and stay at the Sun Valley Lodge which is worth every penny.
So while sure, there are nice amenities there it's up to you whether you want a luxury experience.
8 or so years ago when I skied DV I guess maybe that would have counted as a luxury experience, with the combo of restricted ticket sales, high ticket cost (so, we were paying for the exclusivity), great food (I agree with Susan, you need great food to be considered luxury, and it's not found at most ski areas), and little perks like free sunscreen. I did think that was worth it. It was a weekend and numbers of people were very reasonable. But according to Divas here the ticket sales caps have been lifted to the point of worthlessness, and they are on Ikon, so that would no longer count. If you stay at the Stein Eriksen, where they put your boots on for you, I guess that would give you a luxury experience, as long as you are the kind of person that wants someone else to buckle their boots for them.
I skied little Snoqualmie Summit this morning--a day use area for Seattle people. Not luxury by any stretch. A hamburger there is still $18. I could eat better and cheaper at Sun Valley.