According to sources close to The Inquirer, the mainstream sub $200 market for graphics cards is currently being dominated by the 6600GT AGP and 6600PCIe. NVIDIA is currently on top, it seems, despite strong efforts from ATI.
It took ages for ATI to reduce the prices and to make enough 9800PRO cards available to fight the 6600 GT AGP part and by then Nvidia had already sold shedloads of its own products. ATI dropped the prices of 9800PRO and made it competitive but it should have done this much earlier than it actually did and people were hard to convince to buy those cards as they were based on an older marchitecture.
It seems that ATI's tactic to have the 6600GT price sandwiched between 9800PRO and 9600XT has not paid off, and its lack of SLI support until fairly recently has not helped matters much either. The article suggests that what ATI really needs to do right now is get RV530 out.