Perhaps your daughter is accustomed to an elegant bedroom furniture set outfitted with designer accessories. While she might appreciate a perfectly coordinated and aesthetically pleasing space, it's just not realistic to turn a teeny dorm room into a clone of the Pottery Barn catalog. You can only do so much with metal cabinets and creaky old bunk beds, you know?
Plus, bedding items are pricey, and getting a roommate (especially a potluck one) to pitch in for her share of the textiles isn't going to happen -- nor is it even fair to ask.
Buy the necessities and don't look back. Someday she'll get her own apartment or house, and you'll be able to renew your platinum status at your favorite home store.