Although the custom PowerVR2 chip Dreamcast had was probably technically better in many ways than what 3Dfx was offering, in retrospect Sega should have not canceled their contract with 3Dfx. The console industry would probably be very different today.
IIRC, it was said during the time, and I could be wrong, but one reason EA decided not to support Dreamcast is because it did not use a 3Dfx chip and the GLIDE API which had tremendous support in the late 90s.