@Aloid
Did you mean 5770 outperformed by 4870?
@santa2142
First, ATI has had a die shrink since 4770. Skills and efficiency improves with time and technology. Also, a die shrink would mean lower production cost, although the amount spent on R&D can certainly make up for the reduction in cost. Not to mention economy of scale.
Secondly, the way I see it, ATI is still charging a premium for all its 5000 cards since our beloved green team still does not have theirs out yet. When GT300 comes out, ATI can definitely slash prices like crazy and go on war against them.
The HD4800 came out cheap because nVidia's cards were already in the market. Hence, the only thing ATI could do was to aim for value for money.
However, they are not cheap. Look at 5800 series. They go above $200 where in reality, they should be around the same price (or perhaps slightly higher) as the 4800 series since they are aimed at replacing the 4800 lineup.