Most likely because they don't have to have them so low due to so many rooms being filled already. I, for one, am happy with any discount I can get. I'll take POR for the exact same price I was paying for AllStarMovies. Is that the best rate I've gotten? No, but it's better than what I booked at.
As I've said before...I don't buy an AP for room discounts but for entrance into parks for over 24 days so far this year. If I get any kind of break on my room rate, then terrific.