When considering the entire cost of attendance SC is not alone in being very expensive. If you check out these colleges/universities you will find the cost of attendance is in the same ballpark: Barnard, Sarah Lawrence, Bard, Columbia, Wesleyan, Bennington, Oberlin, Vassar and Tufts.
When the costs of the other colleges in the list are announced for 2016-17 I think you will find the others are in line with SC’s.