when? the nvidia 8800 GTX launched in 2006 at $599 MSRP. it wasn't even the top card of that generation. that would be the 8800 ultra which launched eight months later at $829 MSRP. unless I'm mistaken, you would have to go back to the Ti 4600 to find a flagship GPU that launched at/under $400. that was in 2002.
ten years after the 8800 GTX, I bought a 1080 ti not long after launch for about $650. that card is more than 2000% faster, for roughly the same inflation-adjusted price.
As an aside, as an owner of a x1950 pro at the time it's fun to read old reviews of how sick the 8800 GTX was at launch and think reminisce about thinking of maybe buying a $400 almost as good 8800 GTS someday, while now they're $20 on eBay.
ten years after the 8800 GTX, I bought a 1080 ti not long after launch for about $650. that card is more than 2000% faster, for roughly the same inflation-adjusted price.