Where are you getting these numbers from??
the 8800gs is pants, the only 8800gt it could come close to was the 256mb version which was also rubbish.
the 9600gt always performed slightly below the 3870 not above it.
kalniel does seem a little out of date, but the initial dx10 cards were bad performers except the very top range cards and thoes where very expensive (I seem to remember that the 8800gts 320mb was just over £225)
The situation changed with the release of the 3850 & 3870 and rushed launch of the 8800gt in response. these where not mid range cards but high end cards sold at mid range prices.
And this basic situation is still true today, we have the low-high end cards at the mid range cost of the £100 mark.
the 9600gt and 4670 are now the budget gaming cards and will have overtaken the top end dx9 cards.
That said cards below these are still badly marketed as "gaming" cards even when they really are not up to the task and would be overtaken by older high end dx9 cards
give me the choise of a 9400gt or x1900xtx to game on and it's the x1900xtx, or more probably option C, I'll go out and buy a better one myself.