Not really. 3DFX lost to Nvidia in Riva TNT era,
More like the Riva TNT2 era - the Riva TNT was still a little slower than the Voodoo2 it was competition against, but it did cement Nvidia as a good card that could actually compete (compared to everything else which was basically a toy compared to 3dfx's cards).
That was in 1998 though, 2 years after 3dfx released the original Voodoo which basically was wiping the floor against anything else at the time. Back then you could still choose if you wanted 3d acceleration or the software rendering engine and it was like night and day popping in a Voodoo card.
Granted, a 2-3 year lead doesn't seem like much at the time now almost 30 years later, but still being almost the only player in town for that much time to being completely defunct in a year or two more was still pretty surprising.
I do think the slowness to release a complete card (versus the addon style) cards hurt them too. I didn't end up staying with 3dfx past the Voodo2 line myself.