nvidia sets an MSRP at manufacturers generally fall in line with it.
don't forget that the market is not dominated by nvidia. ATI would be sure to capitalize on nvidia RAISING prices...by staying with their own lower price, or by lowering their already lower price. if a nvidia card suddenly rockets in price by $50-100 do you think people will still buy it over ATI? i know i wouldn't. i would never buy a product from a company that uses underhanded tactics like that(raising MSRP). i think many people would agree with me.
edit: nvidia tried selling the gf3 for $500, but when that price was announced, what happened? please don't insult myself and others and tell us that we "don't get it."
edit#2: maybe someone should tell you that you don't always incur the highest profit by setting the highest price. how many people are going to buy a $400 card every 6 months when games are lagging farther and farther behind? true, the R9700 is the first card where you can basically max out FSAA and AF at super high resolutions and get away with it, but most people don't use those options nor those high resolutions. what i'm getting at is, unless people need extra power, they aren't going to upgrade unless the price is right.