That's way above list price, so what you're seeing is likely more a matter of availability than anything else. Plus, NVIDIA isn't making those cards any more, they're all made by licensees now.
This is purely speculation on my part, but I strongly suspect that down-market demand is heavily affected by whoever's waving their dick in the press about having the current most powerful video card in existence. This creates a brand association in people's mind that "NVIDIA = power, AMD = budget," so they will pay insane price premiums for NVIDIA cards. You'll often see an NVIDIA card here go for $100-$200 more than an AMD card that puts up nearly identical benchmark scores.
And to be fair to NVIDIA, AMD also had serious quality issues a couple years ago, and poor quality is a tough reputation problem to overcome.