Why is John Carmack considered such a big deal?
Wolfenstein 3D and Doom were 2D games that "faked" being 3D. It wasn't until Quake that iD and John Carmack released a true 3D game.
Ultima Underworld came out in early 1992, more than 4 years before Quake. Not only did it come out before Wolfenstein 3D and Doom, but unlike those games, it is actually truly 3D. You can look up and down, swim, jump and even fly, features that John Carmack didn't implement until nearly half a decade later with Quake.
Yet John Carmack is routinely credited as a legendary developer for his pioneering work in 3D gaming. Yet it seems he was late to the party and didn't do anything truly groundbreaking. What am I missing here? Did he do something else I'm unaware of?