I think it's really hard for these companies to survive one "bad" product generation. I mean it's inevitable that every company is going to have generations that for one reason or another aren't as competitive, for a variety of reasons.
The Voodoo 4/5 were a misstep for 3DFX I think, and one they never recovered from. The Geforce 1 was just a more compelling product. What stinks is ATi and S3, etc., had even LESS compelling products, but survived because they were bigger.
Some other examples:
Nvidia had the Geforce 5 series that wasn't as competitive-in that case it was mostly because of Microsoft. Microsoft was angry that Nvidia wouldn't change their Xbox contract after the fact (why would they? Why would they expect them to?) and punished them by working with ATi and hiding the SM 2.0 spec from them until it was way too late. Nvidia's hardware was actually more programmable and designed around the OpenGL spec...which was obviously the logical thing to do, but Microsoft/ATi designed things with 24-bit precision in mind, giving ATi hardware a huge advantage over Nvidia's that did 32-bit.
Intel's Pentium 4 is another example, although they're so powerful they were able to beat the P4 into a solidly competitive chip, and change direction (in some ways, go back to what they had been doing).
It's just a shame when a product cycle or two is enough to kill a company.
Anyone else have a Rendition Verite card? Pretty awesome for the time, though the API was only briefly supported. Tomb Raider and Quake both supported it I think, and looked AMAZING. I kind of want to say it had hardware T&L, way before anything else-it was programmable...maybe.
And GL Quake...oh man, that just changed everything. Yeah, I've got a Voodoo 1 in my basement. Same box now as a TNT1
D
I really liked the TNT1-I've liked Nvidia ever since that, as it just worked, and a few weeks after release the drivers were rock solid and pretty much have been since. Upgraded all the way to a Geforce 2 though for Deus Ex (and seems like really quickly to a Geforce 4...the Geforce 4 lasted probably 5 years for me, but the 2 didn't seem to last very long).