I don't consider NV30 to be an entire failure, if you consider it from a bit different aspect
It still was able to undercut the R300's price wise (NV35 and NV38 to R350 and R360, they were able to undercut the prices) and it offered a better midrange product, based on financials (FX5200 first DX9 low level card, FX5600 and 5600XT ended up in a nice price position after the FX5700 came, FX5700 put it to the 9600 series as well, I think ATI made a mistake in dropping the 9500). So, in reality nVidia seemed to do the same marketing and financials with NV3x that it pulled off with NV4x and G7x...
nVidia sometimes does have the performance crown for some time (the 6800 Ultra, the 7800GTX, both at their launches were the fastest thing on the block) but they always manage to keep prices down in time to compete with ATI, and they gorge out a nice midrange market (FX 5200 still sells today, 9200 doesn't really, and not at a good price poitn, 6200 and 6600 still ship today (so do the FX 5500 and 6500 series) yeah it's a ton of models to ship, but it keeps the sub $100 range flooded with NV parts)
But if you look at ATI's high end parts post R300
9800XT
X850XT
X1800XT
and X1900
they surpass nV's offerings (5900, 6800, 7800, 7900, etc) by a bit, but they manage to run so much cheaper...while a performance tuner can consider a 9800Pro a bargin in it's day compared to an FX 5900 Ultra, the average Joe at compusa won't because the average Joe won't OC their 9800 and take advantage of the chip's potential, they'll consider their 5900 Ultra a good buy for costing $50 to $100 less and offering nearly the same performance, so what that it's bigger?
I don't know much of NV's history regarding NV-ATI competition around the time of the Radeon 7000 and 8000, however I do know some of the scraps between 3dfx and NV...NV managed to do the same thing to 3dfx it's doing to ATI, it would ship features seen in the future, first, and get them done mostly right...
Correct me if I get models wrong here, but with Voodoo3 3dfx didn't have the color depth of, I wanna say TNT2 but it might be the GeForce 256, while the Voodoo3 was still fast
Which is comparable to say, the 6800GT and the X800Pro...both are fast cards, however the 6800 can hold it's SM3.0 and FP32 over the X800 and match it in prices...
It repeats, nVidia cycles products through in a similar manner, keeping prices under their competition while putting out more features where possible, either as an advertising plug to the common guy, or to make an enthusiast consider a slightly slower product in exchange for more features (to make it seem like more of a value: 90% of the power, 80% of the price, 120% of the feature support, that kind of deal)
I'm not sure you can draw direct correlations, because ATI hasn't made some of the same mistakes as 3dfx, they aren't ignoring the consumer market and pushing into the OEM market soley, which is what 3dfx was reported to be attempting to do in 1999 and early 2000...that's just my 2 cents...