We can go on with this but the bottom line is they couldn't keep up with nvidia so they closed shop simple as that. They let be beaten in their own game.
Much more than being about video card profitability, 3DFX was in fact a battle of APIs and the inevitable chicken/egg questions that arise when marketing a new one.
It is an example of how difficult it is to penetrate an established market, even a young one as it was back then, with a new technology
even if it has advantages over existing technology. 3DFX was fighting established investments and interests.
Its very quickly not going to be about 'who has the best thing' but 'who has the deepest pockets and the most powerful friends'.
Unfortunately, good technology and good business don't always align. We see the same thing with current day APIs. We can all smell, see and get frequent proof that Vulkan is a much stronger API for gaming. What do we get? DX12 which is already devolving into commercial bullshit-feature levels that barely get functional hardware out on the market to support it proper, after all, must have new card, must have new OS, and certain GPU cooking companies are keen to shove more advanced feature levels into it depending on the current shareholder's dream.
History repeats.