Eyes doesn't send the entire picture to the brain at once at a constant sampling rate either, they work more like event cameras [0]. Combine this with micro movements of the eye, and specialized brain structures and it's not as easy as saying that because we only need two eyes, robots only need two cameras. Sure, stereo vision might be enough, but what kind of cameras, and what kind of computers do we need to reach feature parity with our own sight?

[0] http://www.rit.edu/kgcoe/iros15workshop/papers/IROS2015-WASR...

Apart from this, our brains (actually brains of all things that have to hunt/be hunted) are extremely good at detecting motion, especially at the peripherals. This makes us extremely good at detecting stuff like a pedestrian who is about to cross the road, or an incoming vehicle from a junction...

I mean, we could be focusing 100% on the road ahead, and can still respond to peripheral events lightning fast..

I think this is why a lack of sleep can quite adversely affect driving. It seems that if you haven't slept well. the "behind the scene" processing takes a hit, which greatly impacts driving capability..