Of course, with the whole 3dfx buyout story, developers have their own opinion about it too. Voodoo Extreme got in contact with The Carmack, who had this to say

.. It was painful to watch 3dfx slip from the archetypical kick-ass technology start up to where they wound up.
I think I would have been happiest to have the PC market divided up between three strong players that all had their act together, but at this point, I'm not too unhappy with the market simplification resulting from 3dfx exiting.

Evil Avatar has posted the thoughts of Epic programmer Tim Sweeney

... 2. This shows the huge importance of keeping up with competition, in terms of cost, features, and product schedule. From a gamer's perspective, the Voodoo's are approximately as good as the GeForce's on average. The GeForce had T&L but few games took advantage of it; the Voodoo had a fill rate advantage. But this was NOT enough. NVidia's cards outsold 3dfx's by a huge margin (especially to OEMs) because of cost advantages, feature advantages (even though no games took advantage of those features at the time), and predictable product schedules.
3. This shows that a company can't "market" its way around core deficiencies -- at least, not for long. The 3dfx guys did an admirable job of hyping up the T-Buffer and FSAA, and if you read the typical magazine reviews, you might have concluded that 3dfx was on par with NVidia's products. But marketing isn't reality -- they were getting their butt kicked by T&L and 32-bit color ...