The pattern has been this of late: AMD releases a very expensive high end video card, Nvidia counters with an even higher performing video card, AMD drops its prices, and continues to drop its prices until it reaches a point where someone will actually purchase one of their cards.
That is what we are seeing right now with these low prices, however some of us recall the $550 7970 when it came out and the $650 290x when it came out. And people actually bought those, so it has not always been the case where AMD has always had reasonably priced video cards in relation to the competition.